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Mount Everest

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Mount Everest
सागरमथ्था (Sagarmāthā)
ཇོ་མོ་གླང་མ (Chomolungma)
Mount-Everest.jpg
Everest's north face from the Tibetan plateau
Highest point
Elevation 8,872 metres (29,108 ft) [1]
Ranked 1st
Prominence 8,848 metres (29,029 ft) 
Ranked 1st
(Notice special definition for Everest)
Isolation 40,008 kilometres (24,860 mi)
Listing Seven Summits
Eight-thousander
Country high point
Ultra
Coordinates 27°59′17″N 86°55′31″E / 27.98806°N 86.92528°E / 27.98806; 86.92528Coordinates: 27°59′17″N 86°55′31″E / 27.98806°N 86.92528°E / 27.98806; 86.92528[2]
Geography
Mount Everest is located in Nepal
Mount Everest
Mount Everest
Location on the Sagarmatha Zone, Nepal - Tibet, China border
Location Solukhumbu District, Sagarmatha Zone, Nepal;
Tingri County, Xigazê, Tibet Autonomous Region, China[3]
Parent range Mahalangur Himal, Himalayas
Climbing
First ascent 29 May 1953
Edmund Hillary and Tenzing Norgay
(First winter ascent 1980 Leszek Cichy and Krzysztof Wielicki[4][5])
Normal route southeast ridge (Nepal)
Aerial photo from the south, behind Nuptse and Lhotse
Tibetan Plateau and surrounding areas above 1600 m with height colour coded.[6][7]
Top down view showing the location of the summit, and its three main faces/sides

Mount Everest, also known in Nepal as Sagarmāthā and in Tibet as Chomolungma, is Earth's highest mountain. Its peak is 8,848 metres (29,029 ft) above sea level.[1] Mount Everest is located in the Mahalangur mountain range in Nepal and Tibet.[8][9] The international border between China (Tibet Autonomous Region) and Nepal runs across Everest's precise summit point. Its massif includes neighbouring peaks Lhotse, 8,516 m (27,940 ft); Nuptse, 7,855 m (25,771 ft) and Changtse, 7,580 m (24,870 ft).

In 1856, the Great Trigonometrical Survey of India established the first published height of Everest, then known as Peak XV, at 8,840 m (29,002 ft). The current official height of 8,848 m (29,029 ft) as recognised by China and Nepal was established by a 1955 Indian survey and subsequently confirmed by a Chinese survey in 1975. In 2005, China remeasured the height of the mountain and got a result of 8844.43 m. An argument regarding the height between China and Nepal lasted 5 years from 2005 to 2010. China argued it should be measured by its rock height which is 8844 m but Nepal said it should be measured by its snow height 8848 m. In 2010, an agreement was finally reached by both sides that the height of Everest is 8,848 m and Nepal recognises China's claim that the rock height of Everest is 8,844 m.[10] In 1865, Everest was given its official English name by the Royal Geographical Society upon a recommendation by Andrew Waugh, the British Surveyor General of India. As there appeared to be several different local names, Waugh chose to name the mountain after his predecessor in the post, Sir George Everest, despite George Everest's objections.[11]

Mount Everest attracts many climbers, some of them highly experienced mountaineers. There are two main climbing routes: one approaching the summit from the southeast in Nepal (known as the standard route) and the other from the north in Tibet, China. While not posing substantial technical climbing challenges on the standard route, Everest presents dangers such as altitude sickness, weather, wind as well as significant objective hazards from avalanches and the Khumbu Icefall. As of 2016, there are well over 200 corpses still on the mountain, with some of them even serving as landmarks.[12][13]

The first recorded efforts to reach Everest's summit were made by British mountaineers. With Nepal not allowing foreigners into the country at the time, the British made several attempts on the north ridge route from the Tibetan side. After the first reconnaissance expedition by the British in 1921 reached 7,000 m (22,970 ft) on the North Col, the 1922 expedition pushed the North ridge route up to 8,320 m (27,300 ft) marking the first time a human had climbed above 8,000 m (26,247 ft). Tragedy struck on the descent from the North col when seven porters were killed in an avalanche. The 1924 expedition resulted in the greatest mystery on Everest to this day: George Mallory and Andrew Irvine made a final summit attempt on 8 June but never returned, sparking debate as to whether they were the first to reach the top. They had been spotted high on the mountain that day but disappeared in the clouds, never to be seen again, until Mallory's body was found in 1999 at 8,155 m (26,755 ft) on the North face. Tenzing Norgay and Edmund Hillary made the first official ascent of Everest in 1953 using the southeast ridge route. Tenzing had reached 8,595 m (28,199 ft) the previous year as a member of the 1952 Swiss expedition. The Chinese mountaineering team of Wang Fuzhou, Gonpo and Qu Yinhua made the first reported ascent of the peak from the North Ridge on 25 May 1960.[14][15]

Western discovery

A map showing the triangles and transects used in the Great Trigonometric Survey of India, this map produced in 1870. The Great Trigonometrical Survey of India was started in April 1802
Mount Everest is located in Nepal.
Mount Everest is located in Nepal.
Location on Earth
Mount Everest relief map
Morning view of Mount Everest from its southern side

In 1802, the British began the Great Trigonometric Survey of India to determine the location and names of the world's highest mountains. Starting in southern India, the survey teams moved northward using giant theodolites, each weighing 500 kg (1,100 lb) and requiring 12 men to carry, to measure heights as accurately as possible. They reached the Himalayan foothills by the 1830s, but Nepal was unwilling to allow the British to enter the country because of suspicions of political aggression and possible annexation. Several requests by the surveyors to enter Nepal were turned down.[16]

The British were forced to continue their observations from Terai, a region south of Nepal which is parallel to the Himalayas. Conditions in Terai were difficult because of torrential rains and malaria. Three survey officers died from malaria while two others had to retire because of failing health.[16]

Nonetheless, in 1847, the British continued the Great Trigonometric survey and began detailed observations of the Himalayan peaks from observation stations up to 240 km (150 mi) away. Weather restricted work to the last three months of the year. In November 1847, Andrew Waugh, the British Surveyor General of India made several observations from the Sawajpore station located in the eastern end of the Himalayas. Kangchenjunga was then considered the highest peak in the world, and with interest he noted a peak beyond it, about 230 km (140 mi) away. John Armstrong, one of Waugh's officials, also saw the peak from a location farther west and called it peak "b". Waugh would later write that the observations indicated that peak "b" was higher than Kangchenjunga, but given the great distance of the observations, closer observations were required for verification. The following year, Waugh sent a survey official back to Terai to make closer observations of peak "b", but clouds thwarted all attempts.[16]

In 1849, Waugh dispatched James Nicolson to the area, who made two observations from Jirol, 190 km (120 mi) away. Nicolson then took the largest theodolite and headed east, obtaining over 30 observations from five different locations, with the closest being 174 km (108 mi) from the peak.[16]

Nicolson retreated to Patna on the Ganges to perform the necessary calculations based on his observations. His raw data gave an average height of 9,200 m (30,200 ft) for peak "b", but this did not consider light refraction, which distorts heights. However, the number clearly indicated that peak "b" was higher than Kangchenjunga. Then, Nicolson contracted malaria and was forced to return home without finishing his calculations. Michael Hennessy, one of Waugh's assistants, had begun designating peaks based on Roman numerals, with Kangchenjunga named Peak IX, while peak "b" now became known as Peak XV.[16]

In 1852, stationed at the survey headquarters in Dehradun, Radhanath Sikdar, an Indian mathematician and surveyor from Bengal, was the first to identify Everest as the world's highest peak, using trigonometric calculations based on Nicolson's measurements.[17] An official announcement that Peak XV was the highest was delayed for several years as the calculations were repeatedly verified. Waugh began work on Nicolson's data in 1854, and along with his staff spent almost two years working on the calculations, having to deal with the problems of light refraction, barometric pressure, and temperature over the vast distances of the observations. Finally, in March 1856 he announced his findings in a letter to his deputy in Calcutta. Kangchenjunga was declared to be 8,582 m (28,156 ft), while Peak XV was given the height of 8,840 m (29,002 ft). Waugh concluded that Peak XV was "most probably the highest in the world".[16] Peak XV (measured in feet) was calculated to be exactly 29,000 ft (8,839.2 m) high, but was publicly declared to be 29,002 ft (8,839.8 m) in order to avoid the impression that an exact height of 29,000 feet (8,839.2 m) was nothing more than a rounded estimate.[18] Waugh is therefore wittily credited with being "the first person to put two feet on top of Mount Everest".

Name

The next highest mountain in highest elevation above sea level is K2 in modern times.
Dhaulagiri, shown here was thought to be highest before Kanchenjunga and Everest were measured
Kanchenjunga, now determined to be third highest, took over from Dhaulagiri, and in turn surpassed by Everest. K2 was later determined to be 2nd highest, but by the time its height was determined Everest was calculated to be higher.

While the survey wanted to preserve local names if possible (e.g. Kangchenjunga and Dhaulagiri), Waugh argued that he could not find any commonly used local name. Waugh's search for a local name was hampered by Nepal and Tibet's exclusion of foreigners. Many local names existed, including "Deodungha" ("Holy Mountain") in Darjeeling[19] and the Tibetan "Chomolungma", which appeared on a 1733 map published in Paris by the French geographer D'Anville. In the late 19th century, many European cartographers incorrectly believed that a native name for the mountain was Gaurishankar, which is a mountain between Kathmandu and Everest.[20]

Waugh argued that because there were many local names, it would be difficult to favour one name over all others, so he decided that Peak XV should be named after Welsh surveyor Sir George Everest, his predecessor as Surveyor General of India.[16][21][22] Everest himself opposed the name suggested by Waugh and told the Royal Geographical Society in 1857 that "Everest" could not be written in Hindi nor pronounced by "the native of India". Waugh's proposed name prevailed despite the objections, and in 1865, the Royal Geographical Society officially adopted Mount Everest as the name for the highest mountain in the world.[16] The modern pronunciations of Everest (/ˈɛvərst/ and /ˈɛvrst/)[23] are different from Sir George's pronunciation of his surname (/ˈvrst/, EEV-rist).[24]

The Tibetan name for Mount Everest is ཇོ་མོ་གླང་མ (IPA: [t͡ɕʰòmòlɑ́ŋmɑ̀],[citation needed] lit. "Holy Mother"), whose official Tibetan pinyin form is Qomolangma. It is also popularly romanised as Chomolungma and (in Wylie) as Jo-mo-glang-ma or Jomo Langma.[29] The official Chinese transcription is 珠穆朗玛峰 (t 珠穆朗瑪峰), whose pinyin form is Zhūmùlǎngmǎ Fēng ("Chomolungma Peak").[30] It is also infrequently simply translated into Chinese as Shèngmǔ Fēng (t 聖母峰, s 圣母峰, lit. "Holy Mother Peak"). In 2002, the Chinese People's Daily newspaper published an article making a case against the use of "Mount Everest" in English, insisting that the mountain should be referred to as "Mount Qomolangma",[30] based on the official form of the local Tibetan name. The article argued that British colonialists did not "first discover" the mountain, as it had been known to the Tibetans and mapped by the Chinese as "Qomolangma" since at least 1719.[31]

In the early 1960s, the Nepalese government coined a Nepali name for Mount Everest, Sagarmāthā or Sagar-Matha[32] (सागर-मथ्था),[33] allegedly to supplant the Tibetan name among the locals, a usage which the Nepali government felt was "not acceptable".[citation needed]

Surveys

Published by the Survey of Nepal, this is Map 50 of the 57 map set at 1:50,000 scale "attached to the main text on the First Joint Inspection Survey, 1979–80, Nepal-China border." At the top centre, note the boundary line, identified as separating "China" and "Nepal", passing exactly through the summit contour. The boundary here and for much of the China-Nepal border follows the main Himalayan watershed divide.

The 8,848 m (29,029 ft) height given is officially recognised by Nepal and China,[34] although Nepal is planning a new survey.[35]

In 1856, Andrew Waugh announced Everest (then known as Peak XV) as 8,840 m (29,002 ft) high, after several years of calculations based on observations made by the Great Trigonometric Survey.

The elevation of 8,848 m (29,029 ft) was first determined by an Indian survey in 1955, made closer to the mountain, also using theodolites.[citation needed] It was subsequently reaffirmed by a 1975 Chinese measurement of 8,848.13 m (29,029.30 ft).[36] In both cases the snow cap, not the rock head, was measured. In May 1999 an American Everest Expedition, directed by Bradford Washburn, anchored a GPS unit into the highest bedrock. A rock head elevation of 8,850 m (29,035 ft), and a snow/ice elevation 1 m (3 ft) higher, were obtained via this device.[37] Although it has not been officially recognised by Nepal,[38] this figure is widely quoted. Geoid uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 surveys.

A detailed photogrammetric map (at a scale of 1:50,000) of the Khumbu region, including the south side of Mount Everest, was made by Erwin Schneider as part of the 1955 International Himalayan Expedition, which also attempted Lhotse. An even more detailed topographic map of the Everest area was made in the late 1980s under the direction of Bradford Washburn, using extensive aerial photography.[39]

On 9 October 2005, after several months of measurement and calculation, the Chinese Academy of Sciences and State Bureau of Surveying and Mapping officially announced the height of Everest as 8,844.43 m (29,017.16 ft) with accuracy of ±0.21 m (8.3 in). They claimed it was the most accurate and precise measurement to date.[40] This height is based on the actual highest point of rock and not on the snow and ice covering it. The Chinese team also measured a snow/ice depth of 3.5 m (11 ft),[36] which is in agreement with a net elevation of 8,848 m (29,029 ft). The snow and ice thickness varies over time, making a definitive height of the snow cap impossible to determine.

2004 photo mosaic the Himalayas with Makalu and Mount Everest from the International Space Station, Expedition 8.

It is thought that the plate tectonics of the area are adding to the height and moving the summit northeastwards. Two accounts suggest the rates of change are 4 mm (0.16 in) per year (upwards) and 3 to 6 mm (0.12 to 0.24 in) per year (northeastwards),[37][41] but another account mentions more lateral movement (27 mm or 1.1 in),[42] and even shrinkage has been suggested.[43]

Comparisons

PIA15292-Fig2-MarsMountSharp-HeightComparison.jpg

The summit of Everest is the point at which Earth's surface reaches the greatest distance above sea level. Several other mountains are sometimes claimed as alternative "tallest mountains on Earth". Mauna Kea in Hawaii is tallest when measured from its base;[44] it rises over 10,200 m (33,464.6 ft) when measured from its base on the mid-ocean floor, but only attains 4,205 m (13,796 ft) above sea level.

By the same measure of base to summit, Denali, in Alaska, formerly known as Mount McKinley, is also taller than Everest.[44] Despite its height above sea level of only 6,190 m (20,308 ft), Denali sits atop a sloping plain with elevations from 300 to 900 m (980 to 2,950 ft), yielding a height above base in the range of 5,300 to 5,900 m (17,400 to 19,400 ft); a commonly quoted figure is 5,600 m (18,400 ft).[45][46] By comparison, reasonable base elevations for Everest range from 4,200 m (13,800 ft) on the south side to 5,200 m (17,100 ft) on the Tibetan Plateau, yielding a height above base in the range of 3,650 to 4,650 m (11,980 to 15,260 ft).[39]

The summit of Chimborazo in Ecuador is 2,168 m (7,113 ft) farther from Earth's centre (6,384.4 km (3,967.1 mi)) than that of Everest (6,382.3 km (3,965.8 mi)), because Earth bulges at the Equator.[47] This is despite Chimborazo having a peak 6,268 m (20,564.3 ft) above sea level versus Mount Everest's 8,848 m (29,028.9 ft).

Geology

Mount Everest with snow melted, showing upper geologic layers in bands. The "yellow band" can be seen stretching across the mountain.

Geologists have subdivided the rocks comprising Mount Everest into three units called formations.[48][49] Each formation is separated from the other by low-angle faults, called detachments, along which they have been thrust southward over each other. From the summit of Mount Everest to its base these rock units are the Qomolangma Formation, the North Col Formation, and the Rongbuk Formation.

The Qomolangma Formation, also known as the Jolmo Lungama Formation or the Everest Formation,[50] runs from the summit to the top of the Yellow Band, about 8,600 m (28,200 ft) above sea level. It consists of greyish to dark grey or white, parallel laminated and bedded, Ordovician limestone inter layered with subordinate beds of recrystallised dolomite with argillaceous laminae and siltstone. Gansser first reported finding microscopic fragments of crinoids in this limestone.[51][52] Later petrographic analysis of samples of the limestone from near the summit revealed them to be composed of carbonate pellets and finely fragmented remains of trilobites, crinoids, and ostracods. Other samples were so badly sheared and recrystallised that their original constituents could not be determined. A thick, white-weathering thrombolite bed that is 60 m (200 ft) thick comprises the foot of the "Third Step", and base of the summit pyramid of Everest. This bed, which crops out starting about 70 m (230 ft) below the summit of Mount Everest, consists of sediments trapped, bound, and cemented by the biofilms of micro-organisms, especially cyanobacteria, in shallow marine waters. The Qomolangma Formation is broken up by several high-angle faults that terminate at the low angle normal fault, the Qomolangma Detachment. This detachment separates it from the underlying Yellow Band. The lower five metres of the Qomolangma Formation overlying this detachment are very highly deformed.[48][49][53]

The bulk of Mount Everest, between 7,000 and 8,600 m (23,000 and 28,200 ft), consists of the North Col Formation, of which the Yellow Band forms its upper part between 8,200 to 8,600 m (26,900 to 28,200 ft). The Yellow Band consists of intercalated beds of Middle Cambrian diopside-epidote-bearing marble, which weathers a distinctive yellowish brown, and muscovite-biotite phyllite and semischist. Petrographic analysis of marble collected from about 8,300 m (27,200 ft) found it to consist as much as five per cent of the ghosts of recrystallised crinoid ossicles. The upper five metres of the Yellow Band lying adjacent to the Qomolangma Detachment is badly deformed. A 5–40 cm (2.0–15.7 in) thick fault breccia separates it from the overlying Qomolangma Formation.[48][49][53]

The remainder of the North Col Formation, exposed between 7,000 to 8,200 m (23,000 to 26,900 ft) on Mount Everest, consists of interlayered and deformed schist, phyllite, and minor marble. Between 7,600 and 8,200 m (24,900 and 26,900 ft), the North Col Formation consists chiefly of biotite-quartz phyllite and chlorite-biotite phyllite intercalated with minor amounts of biotite-sericite-quartz schist. Between 7,000 and 7,600 m (23,000 and 24,900 ft), the lower part of the North Col Formation consists of biotite-quartz schist intercalated with epidote-quartz schist, biotite-calcite-quartz schist, and thin layers of quartzose marble. These metamorphic rocks appear to be the result of the metamorphism of Middle to Early Cambrian deep sea flysch composed of interbedded, mudstone, shale, clayey sandstone, calcareous sandstone, graywacke, and sandy limestone. The base of the North Col Formation is a regional low-angle normal fault called the "Lhotse detachment".[48][49][53]

Below 7,000 m (23,000 ft), the Rongbuk Formation underlies the North Col Formation and forms the base of Mount Everest. It consists of sillimanite-K-feldspar grade schist and gneiss intruded by numerous sills and dikes of leucogranite ranging in thickness from 1 cm to 1,500 m (0.4 in to 4,900 ft).[49][54] These leucogranites are part of a belt of Late OligoceneMiocene intrusive rocks known as the Higher Himalayan leucogranite. They formed as the result of partial melting of Paleoproterozoic to Ordovician high-grade metasedimentary rocks of the Higher Himalayan Sequence about 20 to 24 million years ago during the subduction of the Indian Plate.[55]

Everest, Khumbu Glacier, Khumbu Icefall

Mount Everest consists of sedimentary and metamorphic rocks that have been faulted southward over continental crust composed of Archean granulites of the Indian Plate during the Cenozoic collision of India with Asia.[56][57][58] Current interpretations argue that the Qomolangma and North Col formations consist of marine sediments that accumulated within the continental shelf of the northern, passive continental margin of India prior to its collision with Asia. The Cenozoic collision of India with Asia subsequently deformed and metamorphosed these strata as it thrust them southward and upward.[59][60] The Rongbuk Formation consists of a sequence of high-grade metamorphic and granitic rocks that were derived from the alteration of high-grade metasedimentary rocks. During the collision of India with Asia, these rocks were thrust downward and to the north as they were overridden by other strata; heated, metamorphosed, and partially melted at depths of over 15 to 20 kilometres (9.3 to 12.4 mi) below sea level; and then forced upward to surface by thrusting towards the south between two major detachments.[61] The Himalayas are rising by about 5 mm per year.

Flora and fauna

There is very little native flora or fauna on Everest. There is a moss that grows at 6,480 metres (21,260 ft) on Mount Everest.[62] It may be the highest altitude plant species.[62] An alpine cushion plant called Arenaria is known to grow below 5,500 metres (18,000 ft) in the region.[63]

Euophrys omnisuperstes, a minute black jumping spider, has been found at elevations as high as 6,700 metres (22,000 ft), possibly making it the highest confirmed non-microscopic permanent resident on Earth. It lurks in crevices and may feed on frozen insects that have been blown there by the wind. It should be noted that there is a high likelihood of microscopic life at even higher altitudes.[64] Birds, such as the bar-headed goose, have been seen flying at the higher altitudes of the mountain, while others, such as the chough, have been spotted as high as the South Col at 7,920 metres (25,980 ft).[65] Yellow-billed choughs have been seen as high as 7,900 metres (26,000 ft) and the aforementioned bar-headed geese migrate over the Himalayas.[66] As early as 1953, George Lowe on the famous expedition of Tenzing and Hillary noted seeing the geese fly over Mount Everest.[67]

A yak at around 4790 m (15715 ft) altitude

Yaks are often used to haul gear for Mount Everest climbs; they can haul 100 kg (220 pounds), and have thick fur and big lungs.[63] One common piece of advice for those in the Everest region is to be on higher ground when around yaks and other animals, as they can knock people off the mountain if standing on the downhill edge of a trail.[68] Other animals in the region include the Himalayan tahr which is sometimes eaten by the snow leopard.[69] The Himalayan black bear can be found up to about 4,300 metres (14,000 ft) and the red panda is also in the region.[70] One science expedition found a surprising range of species in the region including a pika that eats its own faeces and ten new species of ants.[71]

Environment

Atmospheric pressure comparison Pressure Reference
kilopascal psi
Olympus Mons summit 0.03 0.0044
Mars average 0.6 0.087
Hellas Planitia bottom 1.16 0.168
Armstrong limit 6.25 0.906
Mount Everest summit 33.7 4.89 [72]
Earth sea level 101.3 14.69
Dead Sea level 106.7 15.48 [73]
Surface of Venus 9,200 1,330 [74]

In 2008, a new weather station at about 8000 m altitude (26,246 feet) went online.[75] The station's first data in May 2008 were air temperature −17 °C (1 °F), relative humidity 41.3%, atmospheric pressure 382.1 hPa (38.21 kPa), wind direction 262.8°, wind speed 12.8 m/s (28.6 mph, 46.1 km/h), global solar radiation 711.9 watts/m2, solar UVA radiation 30.4 W/m2.[75] The project was orchestrated by Stations at High Altitude for Research on the Environment (SHARE), who also placed the Mount Everest webcam in 2011.[75][76] The weather station is located on the South Col and is solar powered.[77]

Looking at Everest and Lhotse from the south. In the foreground are Thamserku, Kantega, and Ama Dablam

One of the issues facing climbers is the frequent presence of high-speed winds.[78] The peak of Mount Everest extends into the upper troposphere and penetrates the stratosphere,[79] which can expose it to the fast and freezing wind of the jet stream.[80] In February 2004 a wind speed of 280 km/h (175 mph) was recorded at the summit and winds over 160 km/h (100 mph) are common.[78] These winds can blow climbers off Everest. Climbers typically aim for the 7- to 10-day windows in the spring and fall when the Asian monsoon season is either starting up or ending and the winds are lighter. The air pressure at the summit is about one-third what it is at sea level, and by Bernoulli's principle, the winds can lower the pressure further, causing an additional 14% reduction in oxygen to climbers.[80] The reduction in oxygen availability comes from the reduced overall pressure, not a reduction in the ratio of oxygen to other gases.[81]

In the summer, the Indian monsoon brings warm wet air from the Indian ocean to Everest's south side. During the winter the West/South-West flowing jet stream shifts south and blows on the peak.[82]

History of expeditions

Climbers pass by the Yellow Band

Because Mount Everest is the highest mountain in the world, it has attracted considerable attention and climbing attempts. A set of climbing routes has been established over several decades of climbing expeditions to the mountain. Whether the mountain was climbed in ancient times is unknown; it may have been climbed in 1924.

Overview

It was finally known to have been summited by 1953, but it remained a difficult peak for decades.[83] Despite the effort and attention poured into expeditions, it was only summited by about 200 people by 1987.[83] Everest showed itself to be a difficult place for decades, even for serious attempts by professional climbers and large national expeditions, which were the norm until the commercial era picked up in the 1990s.[84]

By March 2012, Everest had been climbed 5,656 times with 223 deaths.[85] Although lower mountains can be longer or steeper climbs, Everest is so high the jet stream can hit it. Climbers can be faced with winds beyond 320 km/h (200 mph) when the weather shifts.[86] At certain times of the year the jet stream shifts north, providing periods of relative calm at the mountain.[87] Other dangers include blizzards and avalanches.[87]

By 2013, the Himalayan database recorded 6,871 summits by 4,042 different people.[88]

Early attempts

In 1885, Clinton Thomas Dent, president of the Alpine Club, suggested that climbing Mount Everest was possible in his book Above the Snow Line.[89]

The northern approach to the mountain was discovered by George Mallory and Guy Bullock on the initial 1921 British Reconnaissance Expedition. It was an exploratory expedition not equipped for a serious attempt to climb the mountain. With Mallory leading (and thus becoming the first European to set foot on Everest's flanks) they climbed the North Col to an altitude of 7,005 metres (22,982 ft). From there, Mallory espied a route to the top, but the party was unprepared for the great task of climbing any further and descended.

The British returned for a 1922 expedition. George Finch ("The other George") climbed using oxygen for the first time. He ascended at a remarkable speed—290 metres (951 ft) per hour, and reached an altitude of 8,320 m (27,300 ft), the first time a human reported to climb higher than 8,000 m. This feat was entirely lost on the British climbing establishment—except for its "unsporting" nature. Mallory and Col. Felix Norton made a second unsuccessful attempt. Mallory was faulted for leading a group down from the North Col which got caught in an avalanche. Mallory was pulled down too, but seven native porters were killed.

The next expedition was in 1924. The initial attempt by Mallory and Geoffrey Bruce was aborted when weather conditions precluded the establishment of Camp VI. The next attempt was that of Norton and Somervell, who climbed without oxygen and in perfect weather, traversing the North Face into the Great Couloir. Norton managed to reach 8,550 m (28,050 ft), though he ascended only 30 m (98 ft) or so in the last hour. Mallory rustled up oxygen equipment for a last-ditch effort. He chose young Andrew Irvine as his partner.

1952 documentary

On 8 June 1924, George Mallory and Andrew Irvine made an attempt on the summit via the North Col/North Ridge/Northeast Ridge route from which they never returned. On 1 May 1999, the Mallory and Irvine Research Expedition found Mallory's body on the North Face in a snow basin below and to the west of the traditional site of Camp VI. Controversy has raged in the mountaineering community whether one or both of them reached the summit 29 years before the confirmed ascent (and of course, safe descent) of Everest by Sir Edmund Hillary and Tenzing Norgay in 1953.

In 1933, Lady Houston, a British millionairess, funded the Houston Everest Flight of 1933, which saw a formation of aircraft led by the Marquess of Clydesdale fly over the summit in an effort to deploy the British Union Flag at the top.[90][91][92]

Early expeditions—such as General Charles Bruce's in the 1920s and Hugh Ruttledge's two unsuccessful attempts in 1933 and 1936—tried to make an ascent of the mountain from Tibet, via the north face. Access was closed from the north to western expeditions in 1950, after China asserted control over Tibet. In 1950, Bill Tilman and a small party which included Charles Houston, Oscar Houston and Betsy Cowles undertook an exploratory expedition to Everest through Nepal along the route which has now become the standard approach to Everest from the south.[93]

The Swiss expedition of 1952, led by Edouard Wyss-Dunant, was granted permission to attempt a climb from Nepal. The expedition established a route through the Khumbu ice fall and ascended to the South Col at an elevation of 7,986 m (26,201 ft). No attempt at an ascent of Everest was ever under consideration in this case.[94] Raymond Lambert and Sherpa Tenzing Norgay were able to reach a height of about 8,595 m (28,199 ft) on the southeast ridge, setting a new climbing altitude record. Tenzing's experience was useful when he was hired to be part of the British expedition in 1953.[95]

First successful ascent by Tenzing and Hillary

In 2015 two mountain ranges on Pluto were named for them, Norgay Montes and Hillary Montes (greyscale image)

In 1953, a ninth British expedition, led by John Hunt, returned to Nepal. Hunt selected two climbing pairs to attempt to reach the summit. The first pair (Tom Bourdillon and Charles Evans) came within 100 m (330 ft) of the summit on 26 May 1953, but turned back after running into oxygen problems. As planned, their work in route finding and breaking trail and their caches of extra oxygen were of great aid to the following pair. Two days later, the expedition made its second and final assault on the summit with its second climbing pair, the New Zealander Edmund Hillary and Tenzing Norgay, a Nepali sherpa climber from Darjeeling, India. They reached the summit at 11:30 am local time on 29 May 1953 via the South Col Route. At the time, both acknowledged it as a team effort by the whole expedition, but Tenzing revealed a few years later that Hillary had put his foot on the summit first.[96] They paused at the summit to take photographs and buried a few sweets and a small cross in the snow before descending.

News of the expedition's success reached London on the morning of Queen Elizabeth II's coronation, 2 June. Returning to Kathmandu a few days later, Hunt (a Briton) and Hillary (a New Zealander) discovered that they had been promptly knighted in the Order of the British Empire for the ascent.[97] Tenzing, a Nepali sherpa who was a citizen of India, was granted the George Medal by the UK. Hunt was ultimately made a life peer in Britain, while Hillary became a founding member of the Order of New Zealand.[98] Hillary and Tenzing are also nationally recognised in Nepal, where annual ceremonies in schools and offices celebrate their accomplishment.[citation needed][99]

The next successful ascent was on 23 May 1956 by Ernst Schmied and Juerg Marmet.[100] This was followed by Dölf Reist and Hans-Rudolf von Gunten on 24 May 1957.[100] Wang Fuzhou, Gonpo and Qu Yinhua of China made the first reported ascent of the peak from the North Ridge on 25 May 1960.[14][15] The first American to climb Everest, Jim Whittaker, joined by Nawang Gombu, reached the summit on 1 May 1963.[101][102]

1970 disaster

This diagram shows some mountaineering routes taken on the southwest face of Everest, including the 1970 Japanese route (did not summit)

In 1970 Japanese mountaineers conducted a major expedition. The centrepiece was a large "siege" style expedition led by Saburo Matsukata, working on finding a new route up the Southwest face.[103] Another element of the expedition was an attempt to ski Mount Everest.[84] Despite a staff of over one hundred people and a decade of planning work, the expedition suffered 8 deaths and failed to summit via the planned routes.[84] However, Japanese expeditions did enjoy some successes. For example, Yuichiro Miura became the first man to ski down Everest from the South Col (he descended nearly 4,200 vertical feet from the South Col before falling with extreme injuries). Another success was an expedition that put four on the summit via the South col route.[84][104][105] Miura's exploits became the subject of film, and he went on to become the oldest person to summit Mount Everest in 2003 at age 70 and again in 2013 at the age of 80.[106] Also, later in the 1970s, the Japanese woman Junko Tabei became the first woman to summit Mount Everest.[84]

1993: Astronaut fatality

Heinze had been and space (see STS-51-F space mission) and co-authored many science papers

One of the extraordinary people claimed by Everest mountaineering was the U.S. astronaut Karl Gordon Henize. He was on a mission to study radiation but came down with a fatal case of HAPE in October 1993 and died at north base camp.[107] At the time he was the oldest astronaut to have flown in space and also had a doctorate in astronomy.[108] He died on October 5, 1993 and was buried on Mount Everest.[109]

1996 disaster

On 11 May 1996 eight climbers died after several expeditions were caught in a blizzard high up on the mountain. During the entire 1996 season, 15 people died while climbing on Mount Everest. These were the highest death tolls for a single event, and for a single season, until the sixteen deaths in the 2014 Mount Everest avalanche. The disaster gained wide publicity and raised questions about the commercialisation of climbing Mount Everest.

Journalist Jon Krakauer, on assignment from Outside magazine, was in one of the affected parties, and afterwards published the bestseller Into Thin Air, which related his experience. Anatoli Boukreev, a guide who felt impugned by Krakauer's book, co-authored a rebuttal book called The Climb. The dispute sparked a debate within the climbing community.

In May 2004, Kent Moore, a physicist, and John L. Semple, a surgeon, both researchers from the University of Toronto, told New Scientist magazine that an analysis of weather conditions on 11 May suggested that freak weather caused oxygen levels to plunge approximately 14%.[110][111]

One of the survivors was Beck Weathers, an American client of New Zealand-based guide service Adventure Consultants. Weathers was left for dead about 275 metres (900 feet) from camp 4 at 7950 metres (26085 feet). After spending a night on the mountain, Weathers managed to find his way to camp 4 with massive frostbite and vision impaired due to snow blindness.[112] When he arrived in camp 4, fellow climbers considered his condition terminal and left him in a tent to die overnight.[113]

They left me alone in Scott Fischer’s tent that night, expecting me to die. On a couple of occasions I heard the others referring to "a dead guy" in the tent. Who could that be? I wondered as I slipped in and out of wakefulness.

— Dr. Beck Weathers[113]

Before leaving camp 4 Jon Krakauer heard Weathers calling for help from his tent. Beck's condition had not improved and an immediate descent to a lower elevation was deemed essential.[113] A helicopter rescue was considered but was out of the question; camp 4 was higher than the rated ceiling of any available helicopter and in any case would be extraordinarily dangerous.[113] Eventually a rescue was organised thanks to a Lieutenant Colonel of the Nepal army who conducted the second-highest known helicopter medical evacuation up to that time.[112]

I will rescue the Beck.

— Lieutenant Colonel Madan K.C.[113]

The storm's impact on climbers on the North Ridge of Mount Everest, where several climbers also died, was detailed in a first-hand account by British filmmaker and writer Matt Dickinson in his book The Other Side of Everest. 16-year-old Mark Pfetzer was on the climb and wrote about it in his account, Within Reach: My Everest Story.

The 2015 feature film Everest, directed by Baltasar Kormákur, is based on the actual events of this disaster.[114]

2006 mountaineering season

Small avalanche on Everest, 2006

In 2006 12 people died. One death in particular (see below) triggered an international debate and years of discussion about climbing ethics.[118][119] The season was also remembered for the rescue of Lincoln Hall who had been left by his climbing team and declared dead, but was later discovered alive and survived being helped off the mountain.

David Sharp ethics controversy

There was an international controversy about the death of a solo British climber David Sharp, who attempted to climb Mount Everest in 2006 but died in his attempt. The story broke out of the mountaineering community into popular media, with a snow-balling series of interviews, allegations, critiques, and peace-making. The question was whether climbers that season had left a man to die, and whether he could have been saved. It seemed to be clear that he had put himself in a very dangerous situation—he was said to have attempted to summit Mount Everest by himself with no Sherpa or guide and fewer oxygen bottles than considered normal.[120] He went with a low-budget Nepali guide firm that only provides support up to Base Camp, after which climbers go as a "loose group", offering a high degree of independence. The manager at Sharp's guide support said Sharp did not take enough oxygen for his summit attempt and did not have a Sherpa guide.[121] It is less clear who knew Sharp was in trouble, and if they did know, whether they were qualified or capable of helping him.[120] Double-amputee climber Mark Inglis revealed in an interview with the press on 23 May 2006, that his climbing party, and many others, had passed Sharp, on 15 May, sheltering under a rock overhang 450 metres (1,480 ft) below the summit, without attempting a rescue.[122] Inglis had said 40 people had passed by Sharp, but he was not aware that Turkish climbers had tried to help him despite being in the process of helping an injured woman down (a Turkish woman named Burçak Poçan). There has also been some discussion about Himex in the commentary on Inglis and Sharp. In regards to the Inglis's initial comments, he later revised certain details because he had been interviewed while he was "...physically and mentally exhausted, and in a lot of pain. He had suffered severe frostbite — he later had five fingertips amputated." When they went through Sharp's possession they found a receipt for $7,490USD, believed to be the whole financial cost.[123] Comparatively, most expeditions are between $30 to $100,000USD plus an additional $20,000 in other expenses that range from gear to bonuses.[124] It was estimated on 14 May that Sharp summitted Mount Everest and began his descent down, but 15 May he was in trouble but being passed by climbers on their way up and down.[125] On 15 May 2006 it is believed he was suffering from hypoxia, and was about 1,000 feet from the summit on the North Side route.[125]

"Dawa from Arun Treks also gave oxygen to David and tried to help him move, repeatedly, for perhaps an hour. But he could not get David to stand alone or even stand resting on his shoulders, and crying, Dawa had to leave him too. Even with two Sherpas it was not going to be possible to get David down the tricky sections below."

— Jamie McGuiness [126]

Some climbers who left him said that the rescue efforts would have been useless and only have caused more deaths.[citation needed] Beck Weathers of the 1996 Mount Everest disaster said that those who are dying are often left behind, and that he himself had been left for dead twice but was able to keep walking.[127] The Tribune of India quoted someone who described what happened to Sharp as "the most shameful act in the history of mountaineering".[128] In addition to David's death, at least nine other climbers perished that year, including multiple Sherpas working for various guiding companies.[129]

"You are never on your own. There are climbers everywhere."

— David Sharp[130]

Much of this controversy was captured by the Discovery Channel while filming the television program Everest: Beyond the Limit. A crucial decision affecting the fate of Sharp is shown in the program, where an early returning climber Lebanese adventurer Maxim Chaya is descending from the summit and radios to his base camp manager (Russell Brice) that he has found a frostbitten and unconscious climber in distress. Chaya is unable to identify Sharp, who had chosen to climb solo without any support and so did not identify himself to other climbers. The base camp manager assumes that Sharp is part of a group that has already calculated that they must abandon him, and informs his lone climber that there is no chance of him being able to help Sharp by himself. As Sharp's condition deteriorates through the day and other descending climbers pass him, his opportunities for rescue diminish: his legs and feet curl from frostbite, preventing him from walking; the later descending climbers are lower on oxygen and lack the strength to offer aid; time runs out for any Sherpas to return and rescue him. Most importantly, Sharp's decision to climb without support left him with no margin for recovery.

David Sharp's body remained just below the summit on the Chinese side next to another corpse nicknamed "Green Boots"; they shared a space in a small rock cave that was an ad hoc tomb for them.[125] Sharp's body was removed from the cave in 2007, according to the BBC,[131] and since 2014, Green Boots has been missing, presumably removed or buried.[132]

Lincoln Hall rescue

As the Sharp debate kicked off, on 26 May 2006 Australian climber Lincoln Hall was found alive, after being declared dead the day before. He was found by a party of four climbers (Dan Mazur, Andrew Brash, Myles Osborne and Jangbu Sherpa) who, giving up their own summit attempt, stayed with Hall and descended with him and a party of 11 Sherpas sent up to carry him down. Hall later fully recovered. Similar actions have been recorded since, including on 21 May 2007, when Canadian climber Meagan McGrath initiated the successful high-altitude rescue of Nepali Usha Bista. Recognising her heroic rescue, Major Meagan McGrath was selected as a 2011 recipient of the Sir Edmund Hillary Foundation of Canada Humanitarian Award, which recognises a Canadian who has personally or administratively contributed a significant service or act in the Himalayan Region of Nepal.[133]

Ascent statistics up to 2010 season

Ascents of Mount Everest by year through 2010
The sun rising on Everest in 2011

By the end of the 2010 climbing season, there had been 5,104 ascents to the summit by about 3,142 individuals, with 77% of these ascents being accomplished since 2000.[134] The summit was achieved in 7 of the 22 years from 1953 to 1974, and was not missed between 1975 and 2014.[134] In 2007, the record number of 633 ascents was recorded, by 350 climbers and 253 sherpas.[134]

A remarkable illustration of the explosion of popularity of Everest is provided by the numbers of daily ascents. Analysis of the 1996 Mount Everest disaster shows that part of the blame was on the bottleneck caused by the large number of climbers (33 to 36) attempting to summit on the same day; this was considered unusually high at the time. By comparison, on 23 May 2010, the summit of Mount Everest was reached by 169 climbers – more summits in a single day than in the cumulative 31 years from the first successful summit in 1953 through 1983.[134]

There have been 219 fatalities recorded on Mount Everest from the 1922 British Mount Everest Expedition through the end of 2010, a rate of 4.3 fatalities for every 100 summits (this is a general rate, and includes fatalities amongst support climbers, those who turned back before the peak, those who died en route to the peak and those who died while descending from the peak). Of the 219 fatalities, 58 (26.5%) were climbers who had summited but did not complete their descent.[134] Though the rate of fatalities has decreased since the year 2000 (1.4 fatalities for every 100 summits, with 3938 summits since 2000), the significant increase in the total number of climbers still means 54 fatalities since 2000: 33 on the northeast ridge, 17 on the southeast ridge, 2 on southwest face, and 2 on north face.[134]

Nearly all attempts at the summit are done using one of the two main routes. The traffic seen by each route varies from year to year. In 2005–07, more than half of all climbers elected to use the more challenging, but cheaper northeast route. In 2008, the northeast route was closed by the Chinese government for the entire climbing season, and the only people able to reach the summit from the north that year were athletes responsible for carrying the Olympic torch for the 2008 Summer Olympics.[135] The route was closed to foreigners once again in 2009 in the run-up to the 50th anniversary of the Dalai Lama's exile.[136] These closures led to declining interest in the north route, and, in 2010, two-thirds of the climbers reached the summit from the south.[134]

2012 mountaineering season

Everest from Gokyo Ri, 2012

In 2012 Montana State University conducted a scientific expedition to Everest.[140] The Everest Education Expedition studied the geology of the Everest massif which includes Everest-Nuptse-Lhotse-Khumbutse, and advanced the state of mineralogy, strain, and predicted rock ages.[140] Of interest was the fossil-bearing limestone that crowns Mount Everest, the nature and impact of ice in the region (such as the icefall), and the overall stratigraphy (including limestone, metamorphic rocks, pelites, and quartzites) [140]

In 2012 the oldest woman to reach the summit up to that time was achieved by Tamae Watanabe at 73 years old[141] She broke her own record from 2002, when she climbed it at the age of 63.[142] The retired office worker lives at the base of Mount Fuji, and had also climbed many other peaks including Denali, the Eiger, and Lhotse.[142] She climbed with a group of four, and beat a competing 72-year-old woman who was trying for the same record.[142]

The death of Canadian climber Shriya Shah-Klorfine in 2012 made headlines and fed a debate about whether inexperienced climbers should be climbing Mount Everest.[143][144] Although she did manage to summit, she did not survive the descent.[144][145] Francys Arsentiev died on descent in 1998 despite the efforts of her husband and a team from Uzbekistan that ran low of bottled oxygen.[146] In 1979, another woman named Hannelore Schmatz successfully summited, but like the other two, became exhausted and ran out of oxygen despite the efforts of her climbing group to save her.[147] Ray Genet, in her climbing party died also, but the two Sherpas survived.[147] In 1984 Yogendra Bahadur Thapa and Ang Dorje died trying retrieve her corpse.[148] Schmatz remained frozen on the mountain, with her eyes frozen open and hair left to blow in the wind, to the emotional disturbance of later climbers in the 1980s and 1990s.[148]

Between 1922 and 2012 it is recorded that at least 233 died climbing Mount Everest.[119] With hundreds of climbers on the most popular route on the most popular days, deaths have become almost too routine as many climbers have accepted that some are just not going to make it, even though they are left with a lingering moral question of if they should have done more to save those in trouble.[119]

"As we passed he raised his arm and looked at us," she said. "He didn't know anyone was there. He was almost dead. He was dead when we came back down."

— Leanna Shuttleworth[119]

National Geographic says that 547 people summited in 2012.[149] Of those that attempted the summit, this was a 57 per cent success rate and a higher rate than the year 2000's 24% success rate.[149] The number of summiters has grown also, with National Geographic comparing the 72 summits in 1990, 145 summits in 2000, and the aforementioned 547 summits in 2012.[149]

The Guinness Book of World Records states that 234 climbers summited in one day in 2012.[150] However, it was one of the deadliest seasons since 1996, with 11 climbers dying on Everest in the spring.[151]

2013 mountaineering season

A look up at Everest from the South Col, 2013.

In 2013, about 340 permits to climb Everest were granted.[152] Since Tenzing and Hillary climbed in the 1950s, about 4,000 people had climbed Everest in the years leading up to 2013.[152] That year, three climbers were attacked by a mob of 100 Sherpas at 21,000 feet altitude.[153] The event was noted as an aberration in the otherwise decades long spirit of teamwork and friendship on the mountain.[153] Dangers other than the elements are not unknown to climbers; for example, in 2013 11 climbers were murdered by Taliban in their base camp in nearby Pakistan while at the 8000er Nanga Parbat.[154] The brawl had various things said about it and one highlight was that Melissa Arnot helped diffusse the fight between three climbers and a mob of Sherpa's.[155] Arnot was friends with both the climbers and the high-altitude workers, and when the brawl happened she managed to bring a halt to the fighting, then spend the better part of an hour negotiating a truce between the mountaineers.[155] Sherpas are famous for going to extraordinary lengths for climbers, being friendly, and very generous in sharing Everest with visitors to Nepal.[155] In this case a group of three climbers accidentally triggered some resentment that been building and this snow-balled into a full-out mob attack on them which was fortunately averted when cooler thinking prevailed.[155] The Nepal authorities and police investigated and removed three ring-leaders and declared that they would try to protect climbers.[155] In a situation vaugley similar to when Pocahontas saved John Smith, the 29-years young Arnot throw herself between the attackers and the climbers being beaten thus averting their possible murder.[155] One fact worked in favour, was that she figured they would be less likely to strike a lady, and once the conversation could started it was possible resolve what the tangle of misunderstandings and emotions that come together to trigger the crisis.[155] Mountaineers are well aware of the confusion and delirium high altitude can trigger, and the nuttiness of client request can wear on Sherpa's who also may not have had the most clear emotions and insight high on the Lhotse face.[156] Once the conversations started, it was possible to resolve the situation.[155]

'I came here to climb Mt. Everest. I came here for the challenge, adventure and type of friendship that has become a mark of this place for me. On this expedition, I have had some of the best times of my life, laughing into the late hours with friends who were supporting each other’s goals. I have had some of the worst times — standing in front of those same friends to protect them from unexplainable violence and anger. Something shifted the balance for a moment. My only hope is that it shifts back quickly, and everyone can resume their jobs, their passion and their goal of climbing.

— M. Arnot on the 2013 Everest season brawl[155]

In 2013 a group of Sherpas attacked one climber and attempted to murder him after he returned to camp.[157] Events including swinging an ice pick at him as he climbed the Lhotse face, making physical contact with his climbing partner, verbal threats, the throwing of a knife which impacted but did not penetrate his skin, and other attacks.[157] This was only preliminary, and one part of the attack was described by the climber as "they told us, "Now we kill you. Now we kill you." One of them threw a big stone into Ueli Steck's face, and he started to bleed. Then they were punching my face, and then kicks and punches and kicks and punches. And stones and so on."[157] The climber was upset because he considered himself a friend of the Sherpa community, had built a school for nearly 400 Sherpa children, and also had funded free evacuations via helicopters for Sherpas.[157] The Nepalese government said if climbers were attacked, actions would be taken against the aggressors.[152] Indeed the Nepal tourism officials removed the three ringleaders of the attack from the Mountain and determined that it was misunderstanding that had sorted out, furthermore they pledge to try to insure the safety of climbers.[155] Sherpas are famous for the most part for their climbing skill and good demeanour, with one Everest climber noting "To a man everyone seems to be absolutely impressed with the Sherpas. Not just their strength on the mountain, which is legendary, but their personalities and their friendliness. They become your friends.” [158] One positive thing to come out of the fight was increased conversations between all the people on the mountain, which help overcome come some of the cultural and language barriers that complicate an already difficult environment.[159] In retrospect on of the main culprits was some ice that came down the mountain after the Sherpa's allowed the three climbers to go above them.[159] On the mountains climbers "life fast and die young"; one Sherpa noted how he talked with Marty Schmidt about the situation—Marty died with his son just a few months later in Avalanche on K2.[159][160] The next year 16 Sherpas died when an ice serac fell on them in the Khumbu.[161]

In 2013 Yuichiro Miura became the oldest person yet to reach the summit, at age 80.[162] Also, a Eurocopter AS350 B3 flown by M. Folini achieved a record breaking rescue at 7,800 m (25,590 ft), by retrieving fallen climber Sudarshan Gautam between Camps III & IV in Everest's Yellow Band on the morning of 20 May 2013.[163][164][165][166] Gautam has no arms or prosthetics but reached the summit on 20 May 2013.[167]

The updated 2013 Himalayan database recorded 658 summits, which brought the total number of summits to 6,871 by 4,042 different people.[88] In comparison, it took 41 years after Tenzing and Hillary to achieve the same number of climbs.[168] This is also greater than 2007's 633 summiters.[169]

2014 avalanche and season

Mount Everest in as seen in 2014

On 18 April 2014, an avalanche hit the area just below the Base Camp 2 at around 0100 UTC (0630 local time) and at an elevation of about 5,900 metres.[170] Sixteen people were killed in the avalanche (all Nepalese guides) and nine more were injured.[171] Sadly, this was not the only tragedy in the region with over 43 killed in the 2014 Nepal snowstorm disaster, and they were not even summiting but rather trekking the Annapurna Circuit.

One positive outcome of the season was a 13-year-old girl, Malavath Purna, reaching the summit, breaking the record for youngest female.[172] Additionally, one team used a helicopter to fly from South base camp to Camp 2 to avoid the Khumbu Icefall, then reached the Everest summit. This team had to use the south side because the Chinese had denied them a permit to climb. Nepal turned Chinese reluctance into a success for the country, with the executive donating tens of thousands of dollars to local hospitals and achieving a new hybrid aviation/mountaneering style—they awarded her the Nepalese International Mountaineer of the Year.[173]

Over 100 people summitted Everest from China (Tibet region), and six from Nepal in the 2014 season.[174] This included 72-year old Bill Burke, the Indian teenage girl and a Chinese woman Jing Wang.[175] Another teen girl summiter was Ming Kipa Sherpa who summited with her big sister Lhakpa Sherpa in 2003, and who achieved the most times for woman to the summit of Mount Everest at that time.[176] (see also Santosh Yadav)

This labelled photo-diagram shows the location of the fatal ice avalanche on the 2014 route, and the revised 2015 route through the Khumbu.

2015 avalanche, earthquake, season

Everest as seen in April 2015

2015 was set to be a record breaking season of climbs, with hundreds of permits issued in Nepal and many additional permits in Tibet (China); however, a magnitude 7.8 earthquake on 25 April 2015 effectively shut down the Everest climbing season.[177] 2015 was the first time since 1974 with no spring summits, as all climbing teams pulled out after the quakes and avalanche.[178][179] One of the reasons for this was the high probability (over 50% according to the USGS) of aftershocks.[180] Indeed, just weeks after the first quake, the region was rattled by a 7.3 magnitude quake and there were also many considerable aftershocks.[181]

On 25 April 2015, an earthquake measuring 7.8 Mw triggered an avalanche that hit Everest Base Camp.[182] 18 bodies were recovered from Mount Everest by the Indian army mountaineering team.[183] The avalanche began on Pumori,[184] moved through the Khumbu Icefall on the southwest side of Mount Everest, and slammed into the South Base Camp.[185]

The quakes trapped hundreds of climbers above the Khumbu icefall, and they had to be evacuated by helicopter as they ran low on supplies.[186] The quake shifted the route through the icefall making it essentially unpassable to the climbers.[186] Bad weather also made helicopter evacuation difficult.[186] The Everest tragedy was small compared the impact overall on Nepal, with almost 9 thousand dead in Nepal[187][188] and about 22 thousand injured.[187] In Tibet (China) by 28 April it was identified that at least 25 had died and 117 were injured.[189] By 29 April 2015, the Tibet Mountaineering Association (North/Chinese side) closed Everest and other peaks to climbing, stranding 25 teams and about 300 people on the north side of Everest.[190] On the south side helicopters evacuated 180 people trapped at Camps 1 and 2.[191]

Mountain re-opens in August 2015

On 24 August 2015 Nepal re-opened Everest to tourism including mountain climbers.[192] The only climber permit for the autumn season was awarded to Japanese climber Nobukazu Kuriki, who had tried four times previously to summit Everest without success. He made his fifth attempt in October, but had to give up just 700 metres from the summit due to "strong winds and deep snow".[193][194] Kurki noted the dangers of climbing Everest, having himself survived being stuck in a freezing snow-hole for two days near the top, which came at the cost of all his finger tips and his thumb, lost to frostbite, which added further difficulty to his climb.[195]

Some sections of the trail from Lukla to Everest Base Camp (Nepal) were damaged in the earthquakes earlier in the year and needed repairs to handle trekkers.[196]

2016 season

Mount Everest as seen in May 2016, with Nuptse and Lhotse peaks to the upper right

The Nepal Department of Tourism said by June 2016 that about 456 people made it to summit of Mount Everest, including 45 women.[197] They noted some good summit windows and on one day, 19 May 2016, 209 made it to the summit.[197] By May 11, 2016 the lines were fixed on the south side of Everest after which several hundred climbers would make it up in the critical weather windows.[198]

On 11 May 2016 nine Sherpas summited Mount Everest. The next day another six people reached the top.[199] These were the first summitings since 2014, when 106 made it to the top.[200] By 13 May, 42 climbers had reached the summit[201] and by 22 May, good weather had allowed over 400 climbers to reach the summit. However, about 30 climbers developed frostbite or became sick and two climbers died from what was reported as possible altitude sickness.[202] (see fatalities section for additional reports) Among those that had to turn back, was a science expedition attempting to study the link between hypoxia and cognitive decline.[203] Although it did not run its course it did give some clues into the effects of high-altitude acclimatisation on human blood.[203]

Adrian Ballinger and Cory Richards were sponsored by Eddie Bauer to do an Everest climb, and they relayed information from the Everest climb using the smartphone software application and service Snapchat.[204] Mount Everest has had a 3G wireless data communication network since 2010.[205] One of the things that was reported by them, was that bottled oxygen was stolen from them and there was some bad behaviour up there.[206] The bottled oxygen was there for emergency back-up if they ran into trouble.[206] Cor Richards achieved summiting Mount Everest without oxygen and returned safely, and Adrian made it almost to the top also.[206] Another famous mountaineer, British climber Kenton Cool achieved his 12th Everest summit (the second highest number of Everest summitings for a foreigner after Dave Hahn),[199] and U.S. celebrity mountaineer Melissa Arnot, completed her sixth summit, and achieved her personal goal of climbing Everest without supplementary bottled oxygen.[207] This also turned out to be the most summits for a foreign female (Not Nepali or Chinese), and one of the first U.S. woman to summit and survive without supplementary oxygen.[207] In 1998 Francys Arsentiev had made it to the summit but died during the descent; she went on to become a famous corpse-landmark known as "Sleeping Beauty" until she was buried on Everest in 2007 by one of the people that had tried help her.[208] Another woman from the Americas, the Ecuadorian woman Carla Perez also summited Mount Everest in 2016 without supplementary oxygen.[209] Perez and Arnot became the 5 and 6 women to summit Everest without supplementary oxygen as reported by the The Guardian.[209] There is something of an ongoing discussion about the use of extra bottled oxygen in mountaineering.[209] Bottled oxygen is really just the start of slippery slope that goes beyond acclimatisation.[210] The elephant in the room is Dexamethasone, which is extremely valuable as a life-saver because it can reduce swelling in the brain if someone comes down with HACE but has nevertheless may have become popular.[210] One climbing magazine called it "Climbing's Little Helper" and linked it to several high-altitude mountaineering medical crisis and even fatalities.[211] When American Bill Burke was interviewed for his attempt, he noted how one of his team-members had overdosed on Dex causing a medical evacuation even as in his more recent expedition someone had 25 doses of dex.[212] He also noted it was hard to argue against large supplies of dex, due its life-saving properties against some types of altitude sickness, especially cerebral oedema (HACE).[212] An example of a death in which dex was implicated was Dr. Eberhard Schaaf in 2012 on Everest.[211] Schaaf died on descent at the south summit from altitude sickness.[213] It has a good reputation as a life saver, and is commonly given to Everest climbers for its ability to intervene in last desperate moments when altitude sickness sets in. For example, in the 2016 season Robert Gropel said he gave dex to his wife (as reported by the Telegraph) in attempt to save her as they tried to descend Everest.[214] Of course, Dex is just the tip of the iceberg, with the UIAA noting the aforementioned dexamethasone, but also acetazolamide (aka Diamox), amphetamine, and alcohol use;[215] and another noted Diamox (acetazolamide) use among trekkers.[216] Its not really a matter of some authorities being for or against medications, but awareness, as misuse can cause drug interactions and various side effects.[216] In particular it was noted that supplementary oxygen significantly lowers death rate on ultra-high altitude mountain climbing, and is generally not regulated as a drug, whereas the safe use of medications is less understood or even acknowledged in many cases.[216] (See also Effects of high altitude on humans)

“We estimate that during our informal survey on Everest spring 2012, at least two thirds of climbers we contacted were prescribed several performance enhancing drugs (PEDs) and had intent to use them not for rescue, but to increase their chances of summit success“

— Dr. L. Freer of Everest ER[216]

Mexican-American David Liaño Gonzalez (aka David Liano) summited for the sixth time, promoting a charity and also bringing a Seattle Seahawks fan flag with him to the Everest summit.[217][218] Another sports team represented at the Everest summit was the Denver Broncos, with their flag unfurled by Kim Hess of Colorado, USA (a state also known for its mountains, "the Rockies").[219] Rounding out U.S. mountaineering was news that a group of soldiers and veterans summited, including some that had been wounded in combat.[220] A British wounded veteran (one-eyed) was also trying to summit but gave up his bid to help some Indian climbers.[221]

Also the first climbers from Sri Lanka, Myanmar, and Tunisia reached the summit of Mount Everest.[222][223][223][224] Only two other people from the North Africa region neighbouring Tunisia have summited Everest, one from Algeria and the other from Morocco.[224] The youngest Australian woman to summit Mount Everest became Alyssa Azar, with her story widely reported in Australian and some international news.[225] She returned to Australia safely, but a bittersweet victory for Australia after the loss of an another Australian woman that was also trying to summit that May with her husband.[225] The youngest Japanese woman also summited (and returned alive) at the age of 19.[198] Another woman record breaker in 2016 was the first woman from Thailand to summit Mount Everest, Napassaporn Chumnarnsit, who was even given a meeting with Prime Minister of Thailand for achievement upon her return.[226][227] The first person with Cystic Fibrosis also summited Mount Everest on their third try.[228] Also, a 61-year old summited with two artificial knees.[229] He had been trying for several years and had lost his Nepali friend Sherpa Nawang Tenzing in the 2015 earthquakes.[229] He was not alone in being grief-stricken, as many climbers connected with Everest mountaineering community lost climbing buddies in two years of disasters.[230] One who narrowly survived the disasters himself climbed this year to bring attention to the disease Lewy Body Dementia which afflicted his dad whom he cared for.[230]

Rescues and fatalities

A one-eyed British war veteran rescued a woman from India who was in trouble on her descent.[221] As reported by the BBC, the climber, Leslie Binns, successfully rescued her and tried to save another from her ill-fated eleven-person expedition which suffered three fatalties.[221] About 500 metres from the summit, which he could see with his one eye, he heard a woman screaming for help so he gave up his summit bid to help her down.[235] She had run out of bottled oxygen and was getting frostbitten.[235]

On 11 May 2016 a Canadian doctor from Calgary died in Tibet, in the Chinese-side base camp.[236] A 25-year old Nepali fixing lines near the Lhotse summit fell, named Phurba Sherpa (note: this name is shared by other well-known Sherpas).[237] A guide company called Arnold Coster Expeditions suffered two fatalities, and third client had to be airlifted out.[238] One was a man from the The Netherlands, and another was a South African born Australian woman.[238] Her husband had tried to save her, but he also ran into trouble and had to be air-lifted out with medical complications.[238] These deaths were very widely reported in international news and triggered some public discussion about Everest mountaineering and tourism.[237][238]

A Indian expedition from West Bengal suffered a great tragedy, with the single expedition suffering three fatalities and third, a mother of an 11-year old had to be rescued on her way down.[238] At first it was reported one died and two were missing, but later the other two were located and had not survived.[238] One British climber gave up his summit bid to help a Bengali woman that had fallen and was ailing on her descent.[239] She was further evacuated by the Himalayan Rescue Association and airlifted to Kathmandu with bad frostbite injuries.[240] They were part of an eleven-member expedition from India, and eight reached the summit including the woman[240]

The death toll for Everest climbers rose to 5 in most reports by late May 2016, and with a death of a high-altitude worker on Lhotse face during the season (Everest summiters sometimes need to climb Lhotse face depending on the route), gives a total of 6 known deaths from the Everest massif by the time the season drew to a close.[233] Although not widely reported during May, a climber in Tibet had died on 11 May 2016 which makes it possibly six for Mount Everest and seven for the Everest Massif.[236] The Nepal ministry of tourism said five people died (for the Nepal side).[197]

Climbing

Permits

There were 334 climbing permits issued in 2014, these were extended for free because of the tragedy that struck. In 2015 there was 357 permits to climb Everest, but the mountain was closed again because of the avalanche and earthquake. Nepal then extended the unused 2014/15 permits until 2019 (Nepali permits cost about 10,000 USD for foreigners). So people who bought a permit in 2014 or 2015 can still use it for an expedition to Everest until 2019 (normally they are only valid for one year).[241][clarification needed] This was an example of hospitality that Nepali's have become famous for; an extension was especially requested by expedition firms (which in turn bring resources into the country due for mountaineering). Nepal is essentially a "fourth world" country, one of the poorest non-African countries and the 19th poorest country in the world.[242][242][242] Despite this, Nepal has been very welcoming to tourists and a significant tourism industry has been established.[241]

Routes

Overview South Col route and North Col/Ridge route

Mt. Everest has two main climbing routes, the southeast ridge from Nepal and the north ridge from Tibet, as well as many other less frequently climbed routes.[243] Of the two main routes, the southeast ridge is technically easier and is the more frequently used route. It was the route used by Edmund Hillary and Tenzing Norgay in 1953 and the first recognised of fifteen routes to the top by 1996.[243] This was, however, a route decision dictated more by politics than by design as the Chinese border was closed to the western world in the 1950s after the People's Republic of China invaded Tibet.[244]

Most attempts are made during May before the summer monsoon season. As the monsoon season approaches, a change in the jet stream at this time pushes it northward, thereby reducing the average wind speeds high on the mountain.[245][246] While attempts are sometimes made after the monsoons in September and October, when the jet stream is again temporarily pushed northward, the additional snow deposited by the monsoons and the less stable weather patterns (tail end of the monsoon) makes climbing extremely difficult.

Southeast ridge

The ascent via the southeast ridge begins with a trek to Base Camp at 5,380 m (17,700 ft) on the south side of Everest in Nepal. Expeditions usually fly into Lukla (2,860 m) from Kathmandu and pass through Namche Bazaar. Climbers then hike to Base Camp, which usually takes six to eight days, allowing for proper altitude acclimatisation in order to prevent altitude sickness.[247] Climbing equipment and supplies are carried by yaks, dzopkyos (yak-cow hybrids) and human porters to Base Camp on the Khumbu Glacier. When Hillary and Tenzing climbed Everest in 1953, the British expedition that they were part of (over 400 climbers, porters and sherpas at that point) started from the Kathmandu Valley, as there were no roads further east at that time.

Climbers spend a couple of weeks in Base Camp, acclimatising to the altitude. During that time, Sherpas and some expedition climbers set up ropes and ladders in the treacherous Khumbu Icefall. Seracs, crevasses and shifting blocks of ice make the icefall one of the most dangerous sections of the route. Many climbers and Sherpas have been killed in this section. To reduce the hazard, climbers usually begin their ascent well before dawn, when the freezing temperatures glue ice blocks in place. Above the icefall is Camp I at 6,065 metres (19,900 ft).

Climber traversing Khumbu Icefall

From Camp I, climbers make their way up the Western Cwm to the base of the Lhotse face, where Camp II or Advanced Base Camp (ABC) is established at 6,500 m (21,300 ft). The Western Cwm is a flat, gently rising glacial valley, marked by huge lateral crevasses in the centre, which prevent direct access to the upper reaches of the Cwm. Climbers are forced to cross on the far right near the base of Nuptse to a small passageway known as the "Nuptse corner". The Western Cwm is also called the "Valley of Silence" as the topography of the area generally cuts off wind from the climbing route. The high altitude and a clear, windless day can make the Western Cwm unbearably hot for climbers.[248]

From ABC, climbers ascend the Lhotse face on fixed ropes up to Camp III, located on a small ledge at 7,470 m (24,500 ft). From there, it is another 500 metres to Camp IV on the South Col at 7,920 m (26,000 ft). From Camp III to Camp IV, climbers are faced with two additional challenges: the Geneva Spur and the Yellow Band. The Geneva Spur is an anvil shaped rib of black rock named by the 1952 Swiss expedition. Fixed ropes assist climbers in scrambling over this snow-covered rock band. The Yellow Band is a section of interlayered marble, phyllite, and semischist, which also requires about 100 metres of rope for traversing it.[248]

On the South Col, climbers enter the death zone. Climbers typically only have a maximum of two or three days that they can endure at this altitude for making summit bids. Clear weather and low winds are critical factors in deciding whether to make a summit attempt. If weather does not cooperate within these short few days, climbers are forced to descend, many all the way back down to Base Camp.

verest base camp.jpg
A view of Everest southeast ridge base camp. The Khumbu Icefall can be seen on the left. In the centre are the remnants of a helicopter that crashed in 2003.
Panoramic view of Sagarmatha National Park-Gorak Shep to Pheriche. Khumbu icefall and Mount Everest are on the right side of the picture.

From Camp IV, climbers begin their summit push around midnight with hopes of reaching the summit (still another 1,000 metres above) within 10 to 12 hours. Climbers first reach "The Balcony" at 8,400 m (27,600 ft), a small platform where they can rest and gaze at peaks to the south and east in the early light of dawn. Continuing up the ridge, climbers are then faced with a series of imposing rock steps which usually forces them to the east into waist-deep snow, a serious avalanche hazard. At 8,750 m (28,700 ft), a small table-sized dome of ice and snow marks the South Summit.[248]

Kangshung Face (the east face) as seen from orbit

From the South Summit, climbers follow the knife-edge southeast ridge along what is known as the "Cornice traverse", where snow clings to intermittent rock. This is the most exposed section of the climb as a misstep to the left would send one 2,400 m (7,900 ft) down the southwest face, while to the immediate right is the 3,050 m (10,010 ft) Kangshung Face. At the end of this traverse is an imposing 12 m (39 ft) rock wall, the Hillary Step at 8,760 m (28,740 ft).[248]

Hillary and Tenzing were the first climbers to ascend this step and they did it with primitive ice climbing equipment and ropes. Nowadays, climbers ascend this step using fixed ropes previously set up by Sherpas. Once above the step, it is a comparatively easy climb to the top on moderately angled snow slopes—though the exposure on the ridge is extreme, especially while traversing large cornices of snow. With increasing numbers of people climbing the mountain in recent years, the Step has frequently become a bottleneck, with climbers forced to wait significant amounts of time for their turn on the ropes, leading to problems in getting climbers efficiently up and down the mountain. After the Hillary Step, climbers also must traverse a loose and rocky section that has a large entanglement of fixed ropes that can be troublesome in bad weather. Climbers typically spend less than half an hour at the summit to allow time to descend to Camp IV before darkness sets in, to avoid serious problems with afternoon weather, or because supplemental oxygen tanks run out.

North ridge route

See also: Three Steps
Mount Everest north face from Rongbuk in Tibet

The north ridge route begins from the north side of Everest in Tibet. Expeditions trek to the Rongbuk Glacier, setting up base camp at 5,180 m (16,990 ft) on a gravel plain just below the glacier. To reach Camp II, climbers ascend the medial moraine of the east Rongbuk Glacier up to the base of Changtse at around 6,100 m (20,000 ft). Camp III (ABC—Advanced Base Camp) is situated below the North Col at 6,500 m (21,300 ft). To reach Camp IV on the north col, climbers ascend the glacier to the foot of the col where fixed ropes are used to reach the North Col at 7,010 m (23,000 ft). From the North Col, climbers ascend the rocky north ridge to set up Camp V at around 7,775 m (25,500 ft). The route crosses the North Face in a diagonal climb to the base of the Yellow Band reaching the site of Camp VI at 8,230 m (27,000 ft). From Camp VI, climbers make their final summit push. Climbers face a treacherous traverse from the base of the First Step: ascending from 8,501 to 8,534 m (27,890 to 28,000 ft), to the crux of the climb, the Second Step: ascending from 8,577 to 8,626 m (28,140 to 28,300 ft). (The Second Step includes a climbing aid called the "Chinese ladder", a metal ladder placed semi-permanently in 1975 by a party of Chinese climbers.[249] It has been almost continuously in place since, and ladders have been used by virtually all climbers on the route.) Once above the Second Step the inconsequential Third Step is clambered over: ascending from 8,690 to 8,800 m (28,510 to 28,870 ft). Once above these steps, the summit pyramid is climbed by a snow slope of 50 degrees, to the final summit ridge along which the top is reached.[250]

Summit

A view from the summit of Mount Everest in May 2013

The routes usually share one spot in common, the summit itself. The summit of Everest has been described as "the size of a dining room table".[251] The summit is capped with snow over ice over rock, and the layer of snow varies from year to year.[252] The rock summit is made of Ordovician limestone and is a low-grade metamorphic rock according to Montana State University.[253] (see survey section for more on its height and about the Everest rock summit)

Below the summit there is an area known as "rainbow valley", filled with dead bodies still wearing brightly coloured winter gear.[148] Down to about 8000 metres is an area commonly called the "death zone", due to the high danger and low oxygen because of the low pressure.[79]

Below the summit the mountain slopes downward to the three main sides, or faces, of Mount Everest: the North Face, the South-West Face, and the East/Kangshung Face.[254]

Death zone

The summit of Mount Everest from the North side

At the higher regions of Mount Everest, climbers seeking the summit typically spend substantial time within the death zone (altitudes higher than 8,000 metres (26,000 ft)), and face significant challenges to survival. Temperatures can dip to very low levels, resulting in frostbite of any body part exposed to the air. Since temperatures are so low, snow is well-frozen in certain areas and death or injury by slipping and falling can occur. High winds at these altitudes on Everest are also a potential threat to climbers.

Another significant threat to climbers is low atmospheric pressure. The atmospheric pressure at the top of Everest is about a third of sea level pressure or 0.333 standard atmospheres (337 mbar), resulting in the availability of only about a third as much oxygen to breathe.[255]

Debilitating effects of the death zone are so great that it takes most climbers up to 12 hours to walk the distance of 1.72 kilometres (1.07 mi) from South Col to the summit.[256] Achieving even this level of performance requires prolonged altitude acclimatisation, which takes 40–60 days for a typical expedition. A sea-level dweller exposed to the atmospheric conditions at the altitude above 8,500 m (27,900 ft) without acclimatisation would likely lose consciousness within 2 to 3 minutes.[257]

In May 2007, the Caudwell Xtreme Everest undertook a medical study of oxygen levels in human blood at extreme altitude. Over 200 volunteers climbed to Everest Base Camp where various medical tests were performed to examine blood oxygen levels. A small team also performed tests on the way to the summit.[258] Even at base camp, the low partial pressure of oxygen had direct effect on blood oxygen saturation levels. At sea level, blood oxygen saturation is generally 98–99%. At base camp, blood saturation fell to between 85 and 87%. Blood samples taken at the summit indicated very low oxygen levels in the blood. A side effect of low blood oxygen is a greatly increased breathing rate, often 80–90 breaths per minute as opposed to a more typical 20–30. Exhaustion can occur merely attempting to breathe.[259]

Lack of oxygen, exhaustion, extreme cold, and climbing hazards all contribute to the death toll. An injured person who cannot walk is in serious trouble, since rescue by helicopter is generally impractical and carrying the person off the mountain is very risky. People who die during the climb are typically left behind. As of 2006, about 150 bodies had never been recovered. It is not uncommon to find corpses near the standard climbing routes.[260]

Debilitating symptoms consistent with high altitude cerebral oedema commonly present during descent from the summit of Mount Everest. Profound fatigue and late times in reaching the summit are early features associated with subsequent death.

— Mortality on Mount Everest, 1921-2006: descriptive study[261]

A 2008 study noted that the "death zone" is indeed where most Everest deaths occur, but also noted that most deaths occur during descent from the summit.[262] A 2014 article in the magazine The Atlantic about deaths on Everest noted that while falling is one of the greatest dangers the DZ presents for all 8000ers, avalanches are a more common cause of death at lower altitudes.[263] However, Everest climbing is more deadly than BASE jumping, although some have combined extreme sports and Everest including a beverage company that had someone base-jumping off Everest in a wingsuit (they did survive, though).[264][265]

Despite this, Everest is safer for climbers than a number of peaks by some measurements, but it depends on the period.[266] Some examples are Kangchenjunga, K2, Annapurna, Nanga Parbat, and the Eiger (especially the nordwand).[266] Mont Blanc has more deaths each year than Everest, with over one hundred dying in a typical year and over eight thousand killed since records were kept.[267] Some factors that affect total mountain lethality include the level of popularity of the mountain, the skill of those climbing, and of course the difficulty of the climb.[267]

Another health hazard is retinal haemorrhages, which can damage eyesight and cause blindness.[268] Up to a quarter of Everest climbers can experience retinal haemorrhages, and although they usually heal within weeks of returning to lower altitudes, in one case a climber went blind and ended up dying in the death zone.[268]

At one o'clock in the afternoon, the British climber Peter Kinloch was on the roof of the world, in bright sunlight, taking photographs of the Himalayas below, "elated, cheery and bubbly". But Mount Everest is now his grave, because only minutes later, he suddenly went blind and had to be abandoned to die from the cold.

— A. McSmith[268]

The team made a huge effort for the next 12 hours to try to get him down the mountain, but to no avail, as they were not successful getting him down the difficult sections.[269] Even for the able, the Everest North-East ridge is a recognised as a challenge, which is why it is so hard to rescue someone who has become incapacitated — it is beyond their ability to save them in such a difficult spot.[269] One way around this situation was pioneer by two Nepali men in 2013, who had intended to paraglide off the summit, had major problem in that they were forced to go through with the plan either way because they had run out of bottle oxygen and supplies.[270] They successfully launched off the summit and para-glided down to Namche in just 42 minutes, without having to climb down the mountain.[270]

Supplemental oxygen

Climber at the summit wearing an oxygen mask

Most expeditions use oxygen masks and tanks above 8,000 m (26,000 ft).[271] Everest can be climbed without supplementary oxygen, but only by the most accomplished mountaineers and at increased risk. Humans do not think clearly with low oxygen, and the combination of extreme weather, low temperatures, and steep slopes often requires quick, accurate decisions. While about 95% of climbers who reach the summit use bottled oxygen in order to reach the top, about 5% of climbers have summitted Everest without supplemental oxygen. The death rate is double for those who attempt to reach the summit without supplemental oxygen.[272] Travelling above 8,000 feet altitude is a factor in cerebral hypoxia.[273] This decrease of oxygen to the brain can cause dementia and brain damage, as well as a host of other symptoms.[274] One study found that Mount Everest may be the highest an acclimatised human could go, but also found that climbers may suffer permanent neurological damage despite returning to lower altitudes.[275]

Brain cells are extremely sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. As a result, brain hypoxia can rapidly cause severe brain damage or death.

— Healthline Website[273]

The use of bottled oxygen to ascend Mount Everest has been controversial. It was first used on the 1922 British Mount Everest Expedition by George Finch and Geoffrey Bruce who climbed up to 7,800 m (25,600 ft) at a spectacular speed of 1000 vertical feet per hour (vf/h). Pinned down by a fierce storm, they escaped death by breathing oxygen from a jury-rigged set-up during the night. The next day they climbed to 8,100 m (26,600 ft) at 900 vf/h—nearly three times as fast as non-oxygen users. Yet the use of oxygen was considered so unsportsmanlike that none of the rest of the Alpine world recognised this high ascent rate.[citation needed] George Mallory himself described the use of such oxygen as unsportsmanlike, but he later concluded that it would be impossible for him to summit without it and consequently used it on his final attempt in 1924.[276] When Tenzing and Hillary made the first successful summit in 1953, they used bottled oxygen, with the expedition's physiologist Griffith Pugh referring to the oxygen debate as a "futile controversy", noting that oxygen "greatly increases subjective appreciation of the surroundings, which after all is one of the chief reasons for climbing."[277] For the next twenty-five years, bottled oxygen was considered standard for any successful summit.

.. although an acclimatised lowlander can survive for a time on the summit of Everest without supplemental oxygen, one is so close to the limit that even a modicum of excess exertion may impair brain function.

— Thomas F. Hornbein in The high-altitude brain [275]

Reinhold Messner was the first climber to break the bottled oxygen tradition and in 1978, with Peter Habeler, made the first successful climb without it. In 1980, Messner summited the mountain solo, without supplemental oxygen or any porters or climbing partners, on the more difficult northwest route. Once the climbing community was satisfied that the mountain could be climbed without supplemental oxygen, many purists then took the next logical step of insisting that is how it should be climbed.[278]

The aftermath of the 1996 disaster further intensified the debate. Jon Krakauer's Into Thin Air (1997) expressed the author's personal criticisms of the use of bottled oxygen. Krakauer wrote that the use of bottled oxygen allowed otherwise unqualified climbers to attempt to summit, leading to dangerous situations and more deaths. The disaster was partially caused by the sheer number of climbers (34 on that day) attempting to ascend, causing bottlenecks at the Hillary Step and delaying many climbers, most of whom summitted after the usual 2 pm turnaround time. He proposed banning bottled oxygen except for emergency cases, arguing that this would both decrease the growing pollution on Everest—many bottles have accumulated on its slopes—and keep marginally qualified climbers off the mountain.

The 1996 disaster also introduced the issue of the guide's role in using bottled oxygen.[279] Guide Anatoli Boukreev's decision not to use bottled oxygen was sharply criticised by Jon Krakauer. Boukreev's supporters (who include G. Weston DeWalt, who co-wrote The Climb) state that using bottled oxygen gives a false sense of security.[280] Krakauer and his supporters point out that, without bottled oxygen, Boukreev could not directly help his clients descend.[281] They state that Boukreev said that he was going down with client Martin Adams,[281] but just below the South Summit, Boukreev determined that Adams was doing fine on the descent and so descended at a faster pace, leaving Adams behind. Adams states in The Climb: "For me, it was business as usual, Anatoli's going by, and I had no problems with that."[282]

The low oxygen can cause a mental fog-like impairment of cognitive abilities described as "delayed and lethargic thought process, clinically defined as bradypsychia" even after returning to lower altitudes.[283] In severe cases, climbers can experience hallucinations. Some studies have found that high-altitude climbers, including Everest climbers, experience altered brain structure.[283] The effects of high altitude on the brain, particularly if it can cause permanent brain damage, continue to be studied.[283]

Autumn climbing

Everest in September 2006, what can bee seen here is how white all the mountains are from snowfall. The increased snowfall in the autumn has made it popular for ski/snow boarding but the increased risk of avalanche from all the snow does not benefit mountaineering

Although generally less popular than spring, Mount Everest has also been climbed in the autumn (also called the "post-monsoon season").[63][284] For example, in 2010 Eric Larsen and five Nepali guides summited Everest in the autumn for the first time in ten years.[284] The first mainland British ascent of Mount Everest (Hillary was from New Zealand), led by Chris Bonnington, was an autumn ascent in 1975.[285] The autumn season, when the monsoon ends, is regarded as more dangerous because there is typically a lot of new snow which can be unstable.[286] However, this increased snow can make it more popular with certain winter sports like skiing and snow boarding.[63] Two Japanese summited in October 1973 also.[287] Chris Chandler and Bob Cormack summited Everest in October 1976 as part of the American Bicentennial Everest Expedition that year, the first Americans to make an autumn ascent of Mt. Everest according to the Los Angeles Times.[288] By the 21st century, summer and autumn can be more popular with skiing and snowboard attempts on Mount Everest.[289] During the 1980s, climbing in autumn was actually more popular than in spring.[290] The U.S. astronaut Karl Gordon Henize died in October 1993 on a fall (autumn) expedition conducting an experiment on radiation. The amount of background radiation increases with higher altitudes.[291]

The mountain has also been climbed in the winter, but that is not popular because of the combination of cold high winds and shorter days.[292] By January the peak is typically battered by 170 mph (270 km/h) winds and the average temperature of the summit is around -33 °F (-36 °C).[63]

Sunset lights up the peak of Everest's North face

Selected climbing records

The Khumbu Icefall in 2005
The Western Cwm ("Coom"), with Everest on the left and Lhotse to the right

By the end of the 2010 climbing season, there had been 5,104 ascents to the summit by about 3,142 individuals.[134] Some notable "firsts" by climbers include:

Summiting with disabilities

Summiting Everest with disabilities such as amputations and diseases has become popular in the 21st century, with stories like that of Sudarshan Gautam, a man with no arms who made it to the top in 2013.[314] A teenager with Down's syndrome made it to Base camp, which has become a substitute for more extreme record-breaking because it carries many of the same thrills including the trip to the Himalayas and rustic scenery.[315] Danger lurks even at base camp though, which was the site where dozens were killed in the 2015 Mount Everest avalanches. Others that have climbed Everest with amputations include Mark Inglis (no legs), Paul Hockey (1 arm only), and Arunima Sinha (1 leg).

Everest and aviation

1988: First climb and glide

On 26 September 1988, having climbed the mountain via the south-east ridge, Jean-Marc Boivin made the first paraglider descent of Everest,[316] in the process creating the record for the fastest descent of the mountain and the highest paraglider flight. Boivin said: "I was tired when I reached the top because I had broken much of the trail, and to run at this altitude was quite hard."[317] Boivin ran 18 m (60 ft) from below the summit on 40-degree slopes to launch his paraglider, reaching Camp II at 5,900 m (19,400 ft) in 12 minutes (some sources say 11 minutes).[317][318] Boivin would not repeat this feat, as he was killed two years later in 1990, base-jumping off Venezuela's Angel Falls.[319]

1991: Hot air balloon flyover

In 1991 four men in two balloons achieved the first hot-air balloon flight over Mount Everest.[320] In one balloon was Andy Elson and Eric Jones (cameraman), and in the other balloon Chris Dewhirst and Leo Dickinson (cameraman).[321] Leo went on to write a book about the adventure called Ballooning Over Everest.[321] The hot-air balloons were modified to function at up to 40,000 feet altitude.[321] Reinhold Messner called one of Leo's panoramic views of Everest, captured on the now discontinued Kodak Kodachrome film, the "best snap on Earth", according to UK newspaper The Telegraph.[322] Dewhirst has offered to take passengers on a repeat of this feat for 2.6 million USD per passenger.[320]

2005: Pilot summits Everest with helicopter

Photo of a Eurocopter AS350 B3 "Squirrel"

In May 2005, pilot Didier Delsalle of France landed a Eurocopter AS350 B3 helicopter on the summit of Mount Everest.[323] He needed to land for two minutes to set the Fédération Aéronautique Internationale (FAI) official record, but he stayed for about four minutes, twice.[323] In this type of landing the rotors stay engaged, which avoids relying on the snow to fully support the aircraft. The flight set rotorcraft world records, for highest of both landing and take-off.[324]

Some press reports suggested that the report of the summit landing was a misunderstanding of a South Col landing, but he had also landed on South Col two days earlier,[325] with this landing and the Everest records confirmed by the FAI.[324] Delsalle also rescued two Japanese climbers at 4,880 m (16,000 ft) while he was there. One climber noted that the new record meant a better chance of rescue.[323]

2011 Paraglide off summit

In 2011 two Nepali paraglided from the Everest Summit to Namche in 42 minutes.[270] They had run out of oxygen and supplies, so it was a very fast way off the Mountain.[270] The duo won National Geographic Adventurers of the Year for 2012 for their exploits.[326] After the paraglide they kayaked to the Indian Ocean, and they had made it to the Bay of Bengal by the end of June 2011.[326] One had never climbed, and one had never para-glided, but together they accomplished a ground-breaking feat.[326] By 2013 footage of the flight was shown on the television Nightline.[327] (see also Kayaking for more on this style of activity)

2014: Helicopter assisted ascent

In 2014 one team used a helicopter to fly from South base camp to Camp 2 to avoid the Khumbu Icefall, then reached the Everest summit. This team had to use the south side because the Chinese had denied them a permit to climb. Ultimately, Chinese reluctance may have been beneficial to Nepalese interests, allowing the government to showcase improved local hospitals and the opportunity for a new hybrid aviation/mountaneering style—which sparked conversations about helicopter use in the mountaineering world.[173] Nepal ended up investigating Wang, and she denied the charge but admitted she did fly some support crew over the Khumbu Icefall to Camp 2 using a helicopter.[328] National Geographic noted how a village festooned Wang with honours after she donated 30,000 USD to the town's hospital.[329] Wang won International Mountaineer of the Year Award from the Nepal government in June 2014.[329]

2016: Helicopter business increases

In 2016 the increased use of helicopters was noted for increased efficiency and for hauling materiel over the deadly Khumbu icefall.[330] In particular it was noted that flights saved icefall porters 80 trips but still increased commercial activity at Everest.[330] After many Nepal died in the icefall in 2014, the government had wanted helicopters to handle more transportation to Camp 1 but this was not possible because of the 2015 deaths and earthquake closing the mountain, so the this was implemented in 2016 (helicopters did prove instrumental in rescuing many people in 2015 though).[330] That summer Bell tested the 412EPI, which conducted a series of tests including hovering at 18,000 feet and flying as high as 20,000 feet altitude near Mount Everest.[331]

Financial cost of guided climbs

Going with a "celebrity guide", usually a well-known mountaineer typically with decades of climbing experience and perhaps multiple Everest summits, can cost over £100,000 as of 2015.[332] On the other hand, a limited support service, offering only some meals at base camp and bureaucratic overhead like a permit, can be as little as 7,000 USD.[123] There are issues with the management of guiding firms in Nepal, and one Canadian woman was left begging for help when her guide firm, which she had paid perhaps 40,000 dollars to, couldn't stop her from dying in 2012.[144] She ran out of bottled oxygen after climbing for 27 hours straight.[144] Despite decades of concern over inexperienced climbers, neither she nor the guide firm had summited Everest before.[144] The communist-controlled Tibetan/Chinese side does not offer much reprieve from the chaos, with it being described as "out of control" due to multiple reports of thefts, threats, etc.[333] By 2015, Nepal was considering requiring that summiters have some experience and wanted to make the mountain safer, and especially increase revenue.[334] One barrier to this is that low-budget firms make money not taking inexperienced climbers to the summit.[335](subscription required) Those turned away by western firms can often find another firm willing to take them for a price—that they return home soon after arriving after base camp, or part way up the mountain.[335] Whereas a western firm will convince those they deem incapable to turn back, other firms simply give people the freedom to choose.[335] Mountain managers can be left with difficult choices, sometimes balancing greed with the safety of tourists; as one bureaucrat for the extremely popular Mont Blanc put it, "Climbing the Mont Blanc is a matter for serious mountaineers. It isn't a trek or a playground to get a mention in the Guinness World Records"[336] Mount Blanc may be an indicator of how extreme Everest can go, a mountain that dwarfs Everest in popularity— and fatalities, with tens of thousands, not hundreds summiting a commensurate increase in fatalities, with over a hundred dying each year.[337] The battle for safety is a struggle there as in the Himalaya's, with another official jokingly noting they want to send Pamela Anderson to rescue tourists (perhaps a nod to her role as a life-guard on the U.S. television show Baywatch).[336]

Commercial climbing

Everest base camp
Gorak Shep is about a three-hour walk to South EBC (Everest Base Camp)[338]

Climbing Mount Everest can be a relatively expensive undertaking for climbers. Climbing gear required to reach the summit may cost in excess of US$8,000, and most climbers also use bottled oxygen, which adds around US$3,000. The permit to enter the Everest area from the south via Nepal costs US$10,000 to US$25,000 per person, depending on the size of the team. The ascent typically starts in one of the two base camps near the mountain, both of which are approximately 100 kilometres (60 mi) from Kathmandu and 300 kilometres (190 mi) from Lhasa (the two nearest cities with major airports); transferring one's equipment from the airport to the base camp may add as much as US$2,000.[citation needed]

By 2016, most guiding services cost between 35 and almost 200 thousand dollars.[335] However, the services offered vary widely and its "buyer beware" when doing deals in Nepal, one of the poorest and least developed countries in the World.[335][339] Tourism is about 4% of Nepal's economy, but Everest is special in that an Everest porter can make nearly double the nations's average wage in a region in which other sources of income have been slow coming.[340]

Beyond this point, costs may vary widely. It is technically possible to reach the summit with minimal additional expenses, and there are "budget" travel agencies which offer logistical support for such trips. However, this is considered difficult and dangerous (as illustrated by the case of David Sharp). Many climbers hire "full service" guide companies, which provide a wide spectrum of services, including acquisition of permits, transportation to/from base camp, food, tents, fixed ropes,[341] medical assistance while on the mountain, an experienced mountaineer guide, and even personal porters to carry one's backpack and cook one's meals. The cost of such a guide service may range from $40,000 to $80,000 per person.[342] Since most equipment is moved by Sherpas, clients of full-service guide companies can often keep their backpack weights under 10 kilograms (22 lb), or hire a Sherpa to carry their backpack for them. By contrast, climbers attempting less commercialised peaks, like Denali, are often expected to carry backpacks over 30 kilograms (66 lb) and, occasionally, to tow a sled with 35 kilograms (77 lb) of gear and food.[343]

According to Jon Krakauer, the era of commercialisation of Everest started in 1985, when the summit was reached by a guided expedition led by David Breashears that included Richard Bass, a wealthy 55-year-old businessman and an amateur mountain climber with only four years of climbing experience.[344] By the early 1990s, multiple companies were offering guided tours to the mountain. Rob Hall, one of the mountaineers who died in the 1996 disaster, had successfully guided 39 clients to the summit prior to that incident.[345]

The degree of commercialisation of Mount Everest is a frequent subject of criticism. Jamling Tenzing Norgay, the son of Tenzing Norgay, said in a 2003 interview that his late father would have been shocked to discover that rich thrill-seekers with no climbing experience were now routinely reaching the summit:

You still have to climb this mountain yourself with your feet. But the spirit of adventure is not there any more. It is lost. There are people going up there who have no idea how to put on crampons. They are climbing because they have paid someone $65,000. It is very selfish. It endangers the lives of others.[346]

Reinhold Messner concurred in 2004:

You could die in each climb and that meant you were responsible for yourself. We were real mountaineers: careful, aware and even afraid. By climbing mountains we were not learning how big we were. We were finding out how breakable, how weak and how full of fear we are. You can only get this if you expose yourself to high danger. I have always said that a mountain without danger is not a mountain. ... High-altitude alpinism has become tourism and show. These commercial trips to Everest, they are still dangerous. But the guides and organisers tell clients, "Don't worry, it's all organised." The route is prepared by hundreds of Sherpas. Extra oxygen is available in all camps, right up to the summit. People will cook for you and lay out your beds. Clients feel safe and don't care about the risks.[347]

However, not all opinions on the subject among prominent mountaineers are strictly negative. For example, Edmund Hillary, who went on record saying that he has not liked "the commercialization of mountaineering, particularly of Mt. Everest"[348] and claimed that "Having people pay $65,000 and then be led up the mountain by a couple of experienced guides ... isn't really mountaineering at all",[349] nevertheless noted that he was pleased by the changes brought to Everest area by the Westerners:

I don't have any regrets because I worked very hard indeed to improve the condition for the local people. When we first went in there they didn't have any schools, they didn't have any medical facilities, all over the years we have established 27 schools, we have two hospitals and a dozen medical clinics and then we've built bridges over wild mountain rivers and put in fresh water pipelines so in cooperation with the Sherpas we've done a lot to benefit them.

— Edmund Hillary[350]

One of the early guided summiters, Richard Bass (of Seven Summits fame) responded in an interview about Everest climbers and what it took to survive there:[351]

Climbers should have high altitude experience before they attempt the really big mountains. People don’t realise the difference between a 20,000-foot mountain and 29,000 feet. It’s not just arithmetic. The reduction of oxygen in the air is proportionate to the altitude alright, but the effect on the human body is disproportionate–an exponential curve. People climb Denali [20,320 feet] or Aconcagua [22,834 feet] and think, "Heck, I feel great up here, I’m going to try Everest." But it’s not like that.

— Richard Bass[351]

Law and order struggles

Some climbers have reported life-threatening thefts from supply caches. Vitor Negrete, the first Brazilian to climb Everest without oxygen and part of David Sharp's party, died during his descent, and theft from his high-altitude camp may have contributed.[352][353]

"Several members were bullied, gear was stolen, and threats were made against me and my climbing partner, Michael Kodas, making an already stressful situation even more dire."

— Anne Parmenter[354]

In addition to theft, Michael Kodas describes in his book High Crimes: The Fate of Everest in an Age of Greed (2008),[355] unethical guides and Sherpas, prostitution and gambling at the Tibet Base Camp, fraud related to the sale of oxygen bottles, and climbers collecting donations under the pretence of removing trash from the mountain.[356][357]

The Chinese side of the Everest in Tibet was called "out of countrol" after one Canadian had all his gear stolen and was abandoned by his Sherpa.[333] Another sherpa helped him get off the mountain safely and gave him some spare gear. Other climbers have also noted missing oxygen bottles, which can be worth hundreds of dollars each. One of the problems is that there are hundreds of climbers passing by people's tents, although the weather can also damage or even blow people's equipment away.[333]

2014 Sherpa strike

On 18 April 2014, in one of the worst disasters to ever hit the Everest climbing community up to that time, 16 Sherpas died in Nepal due to the avalanche that swept them off Mount Everest. In response to the tragedy numerous Sherpa climbing guides walked off the job and most climbing companies pulled out in respect for the Sherpa people mourning the loss.[358][359] Some still wanted to climb but there was really too much controversy to continue that year.[358] One of the issues that was triggered was pre-existing resentment that had been building over unreasonable client requests during climbs.[358] As bad as it was, the death toll was surpassed later that year by the 2014 Nepal snowstorm disaster.

Extreme sports at Mount Everest

This is a paraglider, which have been flown off Everest to lower areas

Mount Everest has been host to other winter sports and adventuring besides mountaineering, including snowboarding, skiing, paragliding, and BASE jumping.

Yuichiro Miura became the first man to ski down Everest in the 1970s (he descended nearly 4,200 vertical feet from the South Col before falling with extreme injuries).[84] Stefan Gatt and Marco Siffredi snowboarded Mount Everest in 2001.[360] Other famous Everest skiers include Davo Karničar of Slovenia, who completed a top to south base camp descent in 2000, Hans Kammerlander of Italy in 1996 on the north side,[361] and Kit DesLauriers of the United States in 2006.[362] In 2006 Tomas Olsson planned to ski down the North face, but his anchor broke while he was rappelling down a cliff in the Norton couloir at about 8500 metres, resulting in his death from a two and a half kilometre fall.[363] Also, Marco Siffredi died in 2002 on his second snow-boarding expedition.[360]

Various types of gliding descents have slowly become more popular, and are noted for their rapid descents to lower camps. In 1986 Steve McKinney led an expedition to Mount Everest,[364] during which he became the first person to fly a hang-glider off the mountain.[318] Frenchman Jean-Marc Boivin made the first paraglider descent of Everest in September 1988, descending in minutes from the south-east ridge to a lower camp.[316] In 2011, two Nepalese made a gliding descent from the Everest summit down 5,000 metres (16,400 ft) in 45 minutes.[365] On 5 May 2013, the beverage company Red Bull sponsored Valery Rozov, who successfully BASE jumped off of the mountain while wearing a wingsuit, setting a record for world's highest BASE jump in the process.[264][265][366]

Everest and religion

The Rongphu Monastery, with Mt. Everest in the background

The southern part of Mt. Everest is regarded as one of several "hidden valleys" of refuge designated by Padmasambhava, a ninth-century "lotus-born" Buddhist saint.[367]

Near the base of the north side of Mt. Everest lies Rongbuk Monastery, which has been called the "sacred threshold to Mount Everest, with the most dramatic views of the world."[368] For Sherpas living on the slopes of Everest in the Khumbu region of Nepal, Rongbuk Monastery was an important pilgrimage site, accessed in a few days of travel across the Himalaya through Nangpa La.[96]

Miyolangsangma, a Tibetan Buddhist "Goddess of Inexhaustible Giving", is believed to have lived at the top of Mt. Everest. According to Sherpa Buddhist monks, Mt. Everest is Miyolangsangma's palace and playground, and all climbers are only partially welcome guests, having arrived without invitation.[367]

The Sherpa people also believe that Mt. Everest and its flanks are blessed with spiritual energy, and one should show reverence when passing through this sacred landscape. Here, the karmic effects of one's actions are magnified, and impure thoughts are best avoided.[367]

Debris management

Former long-time Everest guide and climber Apa Sherpa noted the increased amount of items left by expeditions.[312] Apa organised an expedition to remove 4,000 kg (8,800 lb) of rubbish from the lower part of the mountain and another 1,000 kg (2,200 lb) from higher areas. Removal of things from Everest can be quite dangerous, and in one mission two died trying to remove a single corpse, actually increasing the number of dead bodies on Everest.[148]

The Mount Everest Biogas Project aims to make a bioreactor for converting compost material, especially faeces, into a gas maker.[369] One of the challenges of getting a digester to work near Everest is the cold temperatures which have made it harder to work.[370] The project would install a device at Everest that converts human waste into methane, which can then be used as fuel (for heating, etc.).[370]

Names

Everest (barely visible behind the ridge on the left) and Makalu (more prominent on the right) as seen from Darjeeling, India.
  • Peak XV (British Empire's Survey)[16][21][22]
  • "The Bastard" (Hillary)[371]
  • Romanised Tibetan name: "Chomolongma".[25][26][27][28]
  • Romanised Chinese name: "Mount Qomolangma",[30]
  • Romanised Nepalese name: "Sagar-Matha"[32] (Usually Sagarmatha)
  • Old Darjeeling name: "Deodungha"[372]
  • Mount Everest[16]
  • Gauri Shankar, in modern times the name a different peak about 30 miles away, but until about 1900 was also sometimes used.[373]

Maps

Chomo Lonzo Makalu Everest Tibetan Plateau Rong River Changtse Rongbuk Glacier North Face (Everest) East Rongbuk Glacier North Col north ridge route Lhotse Nuptse South Col route Gyachung Kang Cho Oyu File:Himalaya annotated.jpg
Southern and northern climbing routes as seen from the International Space Station. (The names on the photo are links to corresponding pages.)

From China (Tibet region)

Northern panoramic view of Everest from below the Gyatso La on the Friendship Highway between Lhatse and Shelkar

From Gokyo Ri

Annotated image of Everest and surroundings as seen from Gokyo Ri.
Changtse, Nirekha, Everest, Lobuche West, Cho La, Nuptse, Lhotse, Lobuche, Island Peak

Terrain animation

Animation of terrain around Everest and climbing routes by the DLR (Attribution: DLR, CC-BY 3.0)

See also

References

  1. ^ a b Based on the 1999 and 2005 surveys of elevation of snow cap, not rock head. For more details, see Surveys.
  2. ^ The WGS84 coordinates given here were calculated using detailed topographic mapping and are in agreement with adventurestats. They are unlikely to be in error by more than 2". Coordinates showing Everest to be more than a minute further east that appeared on this page until recently, and still appear in Wikipedia in several other languages, are incorrect.
  3. ^ The position of the summit of Everest on the international border is clearly shown on detailed topographic mapping, including official Nepalese mapping.
  4. ^ a b Starr, Daniel (18 March 2011). "Golden Decade: The Birth of 8000m Winter Climbing". Alpinist.com. Retrieved 28 May 2013. 
  5. ^ a b "Mt Everest History and facts". Mnteverest.net. Retrieved 17 June 2016. 
  6. ^ Hastings, D; Dunbar, PK (1999). "Global Land One-kilometer Base Elevation (GLOBE)". National Geophysical Data Center, NOAA. doi:10.7289/V52R3PMS. Retrieved 16 March 2015. 
  7. ^ Amante, C; Eakins, BW (2009). "ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis". National Geophysical Data Center, NOAA. doi:10.7289/V5C8276M. NOAA Technical Memorandum NESDIS NGDC-24. Retrieved 18 March 2015. 
  8. ^ "Trekking in Nepal - Everest Khumbu Region". peakpromotionnepal.com. Retrieved 17 June 2016. 
  9. ^ "The 8 of 10 Highest Mountains of the World Located in Nepal". haminepali.com. 
  10. ^ "Official height for Everest set". BBC. 2010-04-08. Retrieved 2016-08-16. 
  11. ^ "Papers relating to the Himalaya and Mount Everest". Proceedings of the London Royal Geographical Society of London. IX: 345–351. April–May 1857. 
  12. ^ Rachel Nuwer. "BBC - Future - Death in the clouds: The problem with Everest's 200+ bodies". 
  13. ^ Rachel Nuwer (28 November 2012). "There Are Over 200 Bodies on Mount Everest, And They're Used as Landmarks". Smithsonianmag.com. Retrieved 17 June 2016. 
  14. ^ a b c Lewis, Jon E. (1 March 2012). "Appendix 1". The Mammoth Book of How it Happened - Everest. Little, Brown Book Group. p. 212. ISBN 978-1-78033-727-2. 
  15. ^ a b c "Gonpo: first Chinese atop Mount Qomolangma". CCTV. 14 October 2009. 
  16. ^ a b c d e f g h i j Peter Gillman, ed. (1993). Everest – The Best Writing and Pictures from Seventy Years of Human Endeavour. Little, Brown and Company. pp. 10–13. ISBN 978-0-316-90489-6. 
  17. ^ Biswas, Soutik (20 October 2003). "The man who "discovered" Everest". BBC News. Retrieved 11 April 2008. 
  18. ^ "Letters to the Editor". The American Statistician. 36 (1): 64–67. February 1982. doi:10.1080/00031305.1982.10482782. JSTOR 2684102. 
  19. ^ "Mt. Everest 1857". harappa.com. Archived from the original on 26 December 2007. Retrieved 23 January 2008. 
  20. ^ Waddell, LA (December 1898). "The Environs and Native Names of Mount Everest". The Geographical Journal. 12 (6): 564–569. doi:10.2307/1774275. 
  21. ^ a b (India and China). The Times (London). Sat, 4 October 1856. (22490), col B, p. 8.
  22. ^ a b "Papers relating to the Himalaya and Mount Everest". Proceedings of the Royal Geographical Society of London. IX: 345–351. April–May 1857. 
  23. ^ "Mount Everest.". Dictionary.com Unabridged (v 1.1). Random House, Inc. Retrieved 22 July 2009. 
  24. ^ Claypole, Jonty (Director); Kunzru, Hari (Presenter) (2003). Mapping Everest (TV Documentary). London: BBC Television. 
  25. ^ a b "Chomo-lungma: Nepal". Geographical Names. Retrieved 18 April 2014. 
  26. ^ a b "Djomo-lungma: Nepal". Geographical Names. Retrieved 18 April 2014. 
  27. ^ a b "Chomolongma: Nepal". Geographical Names. Retrieved 18 April 2014. 
  28. ^ a b "Mount Jolmo Lungma: Nepal". Geographical Names. Retrieved 18 April 2014. 
  29. ^ Other variants include "Chomo-lungma", "Djomo-lungma", "Jolmo Lungma", and "Chomolongma".[25][26][27][28]
  30. ^ a b c "Qomolangma Feng: Nepal". Geographical Names. Retrieved 18 April 2014. 
  31. ^ "No Longer Everest but Mount Qomolangma". People's Daily Online. 20 November 2002. Retrieved 9 June 2005. 
  32. ^ a b "Sagar-Matha: Nepal". Geographical Names. Retrieved 18 April 2014. 
  33. ^ Unsworth, Walt (2000). Everest – The Mountaineering History (3rd ed.). Bâton Wicks. p. 584. ISBN 978-1-898573-40-1. 
  34. ^ "Nepal and China agree on Mount Everest's height". BBC News. 8 April 2010. Retrieved 22 August 2010. 
  35. ^ "Everest, World's Tallest Mountain, Maybe Not That Tall". Fox News. 20 July 2011. Retrieved 15 August 2013. 
  36. ^ a b "Everest not as tall as thought". News in Science. Australian Broadcasting Corporation. 5 October 2005. Retrieved 1 April 2007. 
  37. ^ a b "Elevation of Mount Everest newly defined". Swiss Foundation for Alpine Research. 12 November 1999. Archived from the original on 3 January 2007. Retrieved 1 April 2007. 
  38. ^ "Country Profile". Government of Nepal. 2001. Archived from the original on 14 March 2007. Retrieved 1 April 2007. 
  39. ^ a b Mount Everest (1:50,000 scale map), prepared under the direction of Bradford Washburn for the Boston Museum of Science, the Swiss Foundation for Alpine Research, and the National Geographic Society, 1991, ISBN 3-85515-105-9
  40. ^ "China says Mount Qomolangma stands at 8844.43". Xinhua online. Xinhua News Agency. 9 October 2005. Retrieved 17 June 2016. 
  41. ^ "Roof of the World". National Geographic Society. 1999. Retrieved 1 April 2007. 
  42. ^ "Everest: Plate Tectonics". Museum of Science. 1998. Archived from the original on 8 November 2006. 
  43. ^ Lim, Louisa (25 January 2005). "China fears Everest is shrinking". BBC News. Retrieved 1 April 2007. 
  44. ^ a b The "base" of a mountain is a problematic notion in general with no universally accepted definition. However, for a peak rising out of relatively flat terrain, such as Mauna Kea or Denali, an approximate height above "base" can be calculated. For Everest the situation is more complicated, since it only rises above relatively flat terrain on its north (Tibetan Plateau) side. Hence the concept of "base" has even less meaning for Everest than for Mauna Kea or Denali, and the range of numbers for "height above base" is wider. In general, comparisons based on "height above base" are somewhat suspect.
  45. ^ "NOVA Online: Surviving Denali, The Mission". NOVA. Public Broadcasting Corporation. 2000. Retrieved 7 June 2007. 
  46. ^ "Mount McKinley 83 feet shorter than thought, new data show". United Press International. 
  47. ^ Robert Krulwich (7 April 2007). "The "Highest" Spot on Earth?". NPR.org. 
  48. ^ a b c d Yin, C.-H. and S.-T. Kuo. 1978. "Stratigraphy of the Mount Jolmo Langma and its north slope." Scientia Sinica. v. 5, pp. 630–644
  49. ^ a b c d e Sakai, H., M. Sawada,Y. Takigami, Y. Orihashi, T. Danhara, H. Iwano, Y. Kuwahara, Q. Dong, H. Cai, and J. Li. 2005. "Geology of the summit limestone of Mount Qomolangma (Everest) and cooling history of the Yellow Band under the Qomolangma detachment." Island Arc. v. 14 no. 4 pp. 297–310.
  50. ^ "Mount Everest, Geology". 
  51. ^ Gansser, A. 1964. Geology of the Himalayas, John Wiley Interscience, London, 1964 289 pp.
  52. ^ Rosenberg, Matt. "A site which uses this dramatic fact first used in illustration of "deep time" in John McPhee's book '''Basin and Range'''". Geology.about.com. Retrieved 17 June 2016. 
  53. ^ a b c Myrow, P. M., N. C. Hughes, M. P. Searle, C. M. Fanning, S.-C. Peng, and S. K. Parcha, 2009, "Stratigraphic correlation of Cambrian Ordovician deposits along the Himalaya: Implications for the age and nature of rocks in the Mount Everest region". Geological Society of America Bulletin. v. 121, no. 3-4, pp. 323–332.
  54. ^ Searle, M.P. (1999) Emplacement of Himalayan leucogranites by magma injection along giant sill complexes: examples from the Cho Oyu, Gyachung Kang and Everest leucogranites (Nepal Himalaya). Journal of Asian Earth Sciences. v. 17, no. 5-6, pp. 773–783.
  55. ^ Guo, Z., and M. Wilson (2012) The Himalayan leucogranites: Constraints on the nature of their crustal source region and geodynamic setting. Gondwana Research. v. 22, no. 2, pp. 360–376.
  56. ^ "Tectonic Motion: Making the Himalayas". Nature on PBS. 11 February 2011. Retrieved 6 February 2016. 
  57. ^ "The Himalayas: Two continents collide". USGS. 5 May 1999. Retrieved 6 February 2016. 
  58. ^ "Press Release: An Earth Plate Is Breaking in Two". 
  59. ^ Myrow, P.M., N.C. Hughes, T.S. Paulsen, I.S. Williams, S.K. Parcha, K.R. Thompson, S.A. Bowring, S.-C. Peng, and A.D. Ahluwalia. 2003. Integrated tectonostratigraphic reconstruction of the Himalaya and implications for its tectonic reconstruction. Earth and Planetary Science Letters. vol. 212, pp. 433-441.
  60. ^ Myrow, P.M., N.C. Hughes, J.W. Goodge, C.M. Fanning, I.S. Williams, S.-C. Peng, O.N. Bhargava, S.K. Tangri, S.K. Parcha, and K.R. Pogue. 2010. Extraordinary transport and mixing of sediment across Himalayan central Gondwanaland during the Cambrian-Ordovician. Geological Society of America Bulletin. vol. 122, pp. 1660-1670.
  61. ^ Searle, M. 2012. Colliding Continents: A geological exploration of the Himalaya, Karakoram, & Tibet. Oxford University Press, Oxford, United Kingdom. 464 pp. ISBN 978-0-19-965300-3
  62. ^ a b "High altitude plant/fungus collection". Adventureandscience.org. Retrieved 15 May 2012. 
  63. ^ a b c d e Ann Heinrichs (1 September 2009). Mount Everest. Marshall Cavendish. p. 25. ISBN 978-0-7614-4649-1. 
  64. ^ Wanless, F.R. (1975). "Spiders of the family Salticidae from the upper slopes of Everest and Makalu". British Arachnological Society. 
  65. ^ The Ascent of Everest by John Hunt (Hodder & Stoughton, 1953) In chapter 14, Hunt describes seeing a chough on the South Col; meanwhile Charles Evans saw some unidentified birds fly over the Col
  66. ^ Jesse Greenspan. "7 Things You Should Know About Mount Everest". HISTORY.com. Retrieved 20 September 2015. 
  67. ^ "Bar-headed geese: Highest bird migration tracked". BBC News. Retrieved 20 September 2015. 
  68. ^ Shaun Francis, Special to National Post (12 October 2012). "Trekking etiquette: Seek higher ground than the yaks or risk a push off the cliff". National Post. Retrieved 20 September 2015. 
  69. ^ Ale, Som B. "Ecology of the Snow Leopard and the Himalayan Tahr in Sagarmatha (Mt. Everest) National Park, Nepal." University of Illinois, 2007. http://www.carnivoreconservation.org/files/thesis/ale_2007_phd.pdf.
  70. ^ "List of Animals on Mount Everest". Animals - mom.me. Retrieved 20 September 2015. 
  71. ^ "Everest Expedition Uncovers Exotic Species". LiveScience.com. Retrieved 20 September 2015. 
  72. ^ West, John B. (1 March 1999). "Barometric pressures on Mt. Everest: new data and physiological significance". J. Applied Physiology. 86: 1062–1066. Retrieved 15 May 2012. 
  73. ^ Cactus Web. "The Dead Sea Region as a Health Resort". Cfcenter.co.il. Retrieved 15 May 2012. 
  74. ^ Basilevsky, Alexandr T.; Head, James W. (2003). "The surface of Venus". Rep. Prog. Phys. 66 (10): 1699–1734. Bibcode:2003RPPh...66.1699B. doi:10.1088/0034-4885/66/10/R04. 
  75. ^ a b c OIKO SERVICE (16 June 2008). "Everest weather station goes online (16 June 2008)". Theuiaa.org. Archived from the original on 5 January 2009. Retrieved 15 May 2012. 
  76. ^ Connelly, Claire (30 September 2011). "Mount Everest webcam gives new meaning to high-def". Herald Sun. Retrieved 30 September 2011. 
  77. ^ da Polenza, Agostino; Vuillermoz, Elisa; Verza, Gian Pietro; Cortinovis, Alberto. "SHARE Everest Automatic Weather Station: South Col, Mt. Everest, Nepal" (PDF). Italy: Ev-K2-CNR Committee. Archived from the original (PDF) on 19 November 2011. 
  78. ^ a b "The deadly odds of climbing Mount Everest: By the numbers". The Week. 
  79. ^ a b godhead/v. "The Open Graveyard of Mt. Everest's "Death Zone"". Gizmodo. Gawker Media. Retrieved 20 September 2015. 
  80. ^ a b "High winds suck oxygen from Everest". Nature.com. 
  81. ^ "Everest: Physiological Effects". thetech.org. Archived from the original on 13 July 2015. Retrieved 20 September 2015. 
  82. ^ "The Climate of Mount Everest". 
  83. ^ a b "Mt. Everest's Popularity Is Still Climbing". latimes. Retrieved 20 September 2015. 
  84. ^ a b c d e f James, Victoria (27 May 2012). "Japan's Everest timeline". The Japan Times. Retrieved 20 February 2016. 
  85. ^ "The World's Tallest Mountain". Earth Observatory. NASA. 2 January 2014. 
  86. ^ "Everest Facts for Kids". 
  87. ^ a b "Window of Opportunity: Everest Climbing Season Underway". Accuweather. 
  88. ^ a b "Everest by the Numbers: The Latest Summit Stats". The Blog on alanarnette.com. Retrieved 20 September 2015. 
  89. ^ William Buxton (12 April 2008). "From First Sight to Summit: A Guide to the Literature on Everest up to the 1953 Ascent" (PDF). Retrieved 23 January 2008. 
  90. ^ "Aeroplane expeditions to Everest". flymicro.com. 
  91. ^ "Wings Over Everest 2003". K2 News. 2002. 
  92. ^ "Flying Over World's Highest Peak". Popular Science. Vol. 122 no. 5. Bonnier Corporation. May 1933. p. 20. 
  93. ^ "Everest History Time Line". Everest History.com. 2003. Retrieved 17 June 2016. 
  94. ^ "Excerpt from: Swiss Foundation for Alpine Research, 1939 to 1970. Published in Zurich in 1972". Archived from the original on 8 March 2011. 
  95. ^ "Tenzing Norgay GM". Retrieved 21 June 2007. 
  96. ^ a b Tenzing Norgay; James Ramsey Ullman (1955). Man of Everest: The Autobiography of Tenzing. also published as Tiger of the Snows. George Harrap & Co, Ltd. 
  97. ^ "The London Gazette". 6 June 1953. Retrieved 27 December 2015. 
  98. ^ "THE ORDER OF NEW ZEALAND (Instituted 1987)". Department of the Prime Minister and Cabinet. Retrieved 27 December 2015. 
  99. ^ "Tribute to Sir Ed Hillary From Nepal". Retrieved 20 September 2010. 
  100. ^ a b "Ernst Schmied". EverestHistory.com. Retrieved 10 April 2010. 
  101. ^ "Jim Whittaker". EverestHistory.com. Retrieved 13 February 2010. 
  102. ^ Isserman, Maurice (February–March 2007). "Highest Adventure". American Heritage. Archived from the original on 3 December 2008. 
  103. ^ Unsworth (2000), p. 594.
  104. ^ "THE JAPANESE MOUNT EVEREST EXPEDITION, 1969-1970". 
  105. ^ "Everest Summits in the 1970's". EverestHistory.com. Retrieved 25 May 2016. 
  106. ^ Associated Press (23 May 2013). "Yuichiro Miura, 80, scales Everest". ESPN. 
  107. ^ [1]
  108. ^ [2]
  109. ^ [3]
  110. ^ "The day the sky fell on Everest". New Scientist (2449): 15. 29 May 2004. Archived from the original on 3 July 2007. Retrieved 11 December 2006. 
  111. ^ Peplow, Mark (25 May 2004). "High winds suck oxygen from Everest Predicting pressure lows could protect climbers.". BioEd Online. Retrieved 11 December 2006. Moore explains that these jet streaks can drag a huge draught of air up the side of the mountain, lowering the air pressure. He calculates that this typically reduces the partial pressure of oxygen in the air by about 6%, which translates to a 14% reduction in oxygen uptake for the climbers. Air at that altitude already contains only one third as much oxygen as sea-level air. 
  112. ^ a b [4]
  113. ^ a b c d e http://www.dmagazine.com/publications/d-magazine/2000/may/my-journey-home-from-everest
  114. ^ Hopewell, John (6 August 2013). "'2 Guns' Helmer Kormakur Set to Climb 'Everest'". variety.com. Retrieved 17 January 2014. 
  115. ^ "Cold mountain: Death on Everest". The Independent. Retrieved 20 September 2015. 
  116. ^ a b "Himalayan Database Expedition Archives of Elizabeth Hawley". himalayandatabase.com. Retrieved 20 September 2015. 
  117. ^ a b "Dispatch 19: Massive Collapse in Khumbu Icefall Claims the Lives of Three Sherpa Climbers". greatoutdoors.com. Retrieved 20 September 2015. 
  118. ^ Ashley Strickland, CNN (25 May 2013). "Striving for Everest: World's highest battle - CNN.com". CNN. Retrieved 20 September 2015. 
  119. ^ a b c d Jon Henley. "Mount Everest: the ethical dilemma facing climbers". the Guardian. Retrieved 20 September 2015. 
  120. ^ a b "Over the Top". Outside Online. Retrieved 20 September 2015. 
  121. ^ "Everest climber left to die alone". The Washingtion Times. Retrieved 20 September 2015. 
  122. ^ "Everest climber defends leaving dying Briton". Australian Broadcasting Corporation. 23 May 2006. Archived from the original on 23 August 2006. 
  123. ^ a b Ed Douglas (13 January 2007). "Summit fever". Telegraph.co.uk. Retrieved 20 September 2015. 
  124. ^ "How Much it Costs to Climb Mount Everest - TIME.com". TIME.com. Retrieved 20 September 2015. 
  125. ^ a b c D. Savage; B. Torgler (25 February 2015). The Times They Are A Changin': The Effect of Institutional Change on Cooperative Behaviour at 26,000ft over Sixty Years. Springer. pp. 5–. ISBN 978-1-137-52515-4. 
  126. ^ "Everest K2 News ExplorersWeb - Jamie McGuiness about David Sharp: "Crying, Dawa had to leave him"". explorersweb.com. Retrieved 20 September 2015. 
  127. ^ "Did Everest Climber Sharp Have to Die?". washingtonpost.com. Retrieved 20 September 2015. 
  128. ^ "The Sunday Tribune - Spectrum". tribuneindia.com. Retrieved 20 September 2015. 
  129. ^ "Everest K2 News ExplorersWeb - Un-named Everest Sherpa gets a name - and fatality details". explorersweb.com. Retrieved 20 September 2015. 
  130. ^ "The Seattle Times: Outdoors: David Sharp's vow on Everest: "If I don't do it this time, I'm not coming back."". seattletimes.com. Retrieved 20 September 2015. 
  131. ^ "Death in the Clouds: The problem with Everest's 200+ bodies". Retrieved 10 October 2015. 
  132. ^ Nuwer, Rachel (9 October 2015). "Death in the clouds: The problem with Everest's 200+ bodies". BBC Future. 
  133. ^ "Sir Edmund Hillary Foundation of Canada". Thesiredmundhillaryfoundation.ca. Retrieved 15 May 2012. 
  134. ^ a b c d e f g h i "Full list of all ascents of Everest up to and including 2010". 8000ers.com. 24 September 2011. Retrieved 28 September 2011. 
  135. ^ Sengupta, Somini (15 March 2008). "Nepal Puts Everest Off Limits During China's Olympic Torch Relay in May". The New York Times. 
  136. ^ Moore, Malcolm (25 February 2009). "China closes Tibetan side of Everest to climbers ahead of anniversary of Dalai Lama's exile". The Daily Telegraph. London. 
  137. ^ "Spring 2012". Himalayan Databaset. Retrieved July 2016.  Check date values in: |access-date= (help)
  138. ^ "Spring 2012". Himalayan Databaset. Retrieved July 2016.  Check date values in: |access-date= (help)
  139. ^ [5]
  140. ^ a b c "Montana State University - Everest Education Expedition - Scientific Research". montana.edu. Retrieved 20 September 2015. 
  141. ^ Ryall, Julian (21 May 2012). "73-year-old becomes oldest woman to climb Mount Everest". London: The Telegraph. Retrieved 22 May 2012. 
  142. ^ a b c Julian Ryall in Tokyo (21 May 2012). "73-year-old becomes oldest woman to climb Mount Everest". Telegraph.co.uk. Retrieved 20 September 2015. 
  143. ^ Grayson Schaffer (24 April 2014). "Five myths about Mount Everest". Washington Post. Retrieved 20 September 2015. 
  144. ^ a b c d e "EXCLUSIVE - Canadian Everest victim used inexperienced company, lacked oxygen". cbc.ca. 14 September 2012. Retrieved 20 September 2015. 
  145. ^ Barbara Amiel. "The lure, and the cruelty, of Mount Everest". Macleans.ca. Retrieved 20 September 2015. 
  146. ^ Rachel Nuwer. "There Are Over 200 Bodies on Mount Everest, And They're Used as Landmarks". Smithsonian. Retrieved 20 September 2015. 
  147. ^ a b Roger Marshall (May 1986). "The King of Everest". Backpacker Magazine. Active Interest Media, Inc. p. 26. 
  148. ^ a b c d Alan Parker. "Everest: 'The open graveyard waiting above' - Macleans.ca". Macleans.ca. Retrieved 20 September 2015. 
  149. ^ a b c "Everest Maxed Out". nationalgeographic.com. Retrieved 20 September 2015. 
  150. ^ "Guinness - Highest mountain". 
  151. ^ Lukas Eberle. "Congestion in the Death Zone: The Story Behind another Deadly Year on Everest". Der Spiegel. 
  152. ^ a b c "A fight at 23,000 feet? Climbers accuse Sherpas of Mount Everest attack". 
  153. ^ a b "What drove 100 Sherpas to attack Western climbers on Everest?". 
  154. ^ Ed Douglas. "Facing down the Taliban on the Himalayas' killer mountain". the Guardian. Retrieved 20 September 2015. 
  155. ^ a b c d e f g h i j [6]
  156. ^ [7]
  157. ^ a b c d "Everest Climber: Sherpas Tried to Kill Me". 
  158. ^ [8]
  159. ^ a b c [9]
  160. ^ [10]
  161. ^ [11]
  162. ^ "Japanese Octogenarian Becomes Oldest Man to Reach Summit of Mount Everest". ABC News. Retrieved 23 May 2013. 
  163. ^ Bierling, Billi (October 2013). "The height of folly?". Action Asia Magazine. When he fell at the Yellow Band during his descent, Gautam then set another landmark: for the highest helicopter rescue in the world. The Italian pilot Maurizio Folini took on the daring task and used a ‘long line’ from 7,800 metres to pull the 30-year-old off the mountain. 
  164. ^ Arnette, Alan (28 February 2014). "Everest 2014: Can I be Rescued on Everest?". 
  165. ^ Sottocornola, Sara (23 May 2013). "Everest, record superato: incredibile recupero vicino a campo 4 per Maurizio Folini". montagna.tv (in Portuguese). 
  166. ^ Wright, Brian (10 June 2013). "Daring High Altitude Rescue on Everest Sets Record". Rock and Ice, The Climber's Magazine. 
  167. ^ Seema Dhawan (23 May 2013). "Sudarshan Gautam Climbs Everest: Armless Calgary Man On Top Of The World". Huffington Post Alberta. Retrieved 3 July 2013. 
  168. ^ Los Angeles Times (22 April 2014). "Climbing Everest shouldn't just be an item on someone's bucket list". latimes.com. Retrieved 20 September 2015. 
  169. ^ "Mount Everest: By the numbers". CNN.com. 
  170. ^ "Everest avalanche kills at least 12 Sherpa guides". BBC News. 18 April 2014. Retrieved 18 April 2014. 
  171. ^ Krakauer, Jon (21 April 2014). "Death and Anger on Everest". The New Yorker. Retrieved 22 April 2014. Of the twenty-five men hit by the falling ice, sixteen were killed, all of them Nepalis working for guided climbing teams. 
  172. ^ "13-year-old Andhra teen becomes youngest woman to scale Everest". Times of India. Retrieved 25 May 2014. 
  173. ^ a b "Woman Whose Post-Avalanche Everest Ascent Sparked Outrage Defends Her Feat". nationalgeographic.com. Retrieved 20 September 2015. 
  174. ^ "Everest 2014: Season Summary - A Nepal Tragedy". The Blog on alanarnette.com. Retrieved 20 September 2015. 
  175. ^ "Everest 2014: Summits - Update 6 - The Blog on alanarnette.com". The Blog on alanarnette.com. 
  176. ^ Luke Harding. "Teenage girl conquers Everest, 50 years on". the Guardian. 
  177. ^ "Everest 2015: Season Summary - Summits Don't Matter". The Blog on alanarnette.com. Retrieved 20 September 2015. 
  178. ^ "Mt. Everest Will Not Be Climbed for First Time Since 1974". snowbrains.com. Retrieved 20 September 2015. 
  179. ^ Parker, Laura (13 May 2015). "Will Everest's Climbing Circus Slow Down After Disasters?". News. National Geographic. Retrieved 6 July 2015. 
  180. ^ "No One Will Climb Everest This Year - The Last Team Pulls Out". snowbrains.com. Retrieved 20 September 2015. 
  181. ^ Nick Rawlinson (15 May 2015). "Nepal earthquake: such huge aftershocks are rare". The Conversation. Retrieved 20 September 2015. 
  182. ^ Gardiner Harris (25 April 2015). "Everest Climbers Are Killed as Nepal Quake Sets Off Avalanche". New York Times. Retrieved 23 December 2015. 
  183. ^ "Avalanche triggered by quake kills 18 on Mount Everest access-date=26 April 2015". 
  184. ^ "Everest Base Camp a 'War Zone' After Earthquake Triggers Avalanches". National Geographic. Retrieved 26 April 2015. 
  185. ^ "10 confirmed dead in Mount Everest avalanche, but toll expected to rise". The Washington Post. 25 April 2015. Retrieved 25 April 2015. 
  186. ^ a b c "Trapped at 20,000 feet: Hundreds of Everest climbers await choppers as supplies run low". 
  187. ^ a b "Incident Report of Earthquake 2015". Nepal Disaster Risk Reduction Portal. drrportal.gov.np. Retrieved 28 May 2015. 
  188. ^ "Nepal earthquake death toll rises to 8,413". The Times of India. 7 May 2015. Retrieved 9 May 2015. 
  189. ^ Press Trust of India (28 April 2015). "Nepal quake: Death toll rises to 25 in Tibet; 117 injured". business-standard.com. Retrieved 17 June 2016. 
  190. ^ "Breaking: North Side of Everest Closing". Outside Online. Retrieved 20 September 2015. 
  191. ^ "Nepal earthquake: Hopes fade for survivors; 180 rescued on Mount Everest". The Sydney Morning Herald. Retrieved 20 September 2015. 
  192. ^ "Mount Everest opens for business". DW.COM. Retrieved 20 September 2015. 
  193. ^ "Japanese climber with no fingertips abandons bid to scale Everest". the Guardian. 
  194. ^ Tanya Basu. "Everest Reopened to Climbers". TIME.com. Retrieved 20 September 2015. 
  195. ^ "Japan finger frostbite victim exposes Nepali desperation to revive Everest climbs". Reuters. Retrieved 20 September 2015. 
  196. ^ "4 sections of trekking route to Mount Everest were damaged by earthquake, assessment finds". Fox News. Retrieved 20 September 2015. 
  197. ^ a b c "Mt Everest records 456 south summits, five deaths". The Himalayan Times. 19 May 2016. Retrieved 17 June 2016. 
  198. ^ a b [12]
  199. ^ a b "Climbers reach Mount Everest summit for the first time in 2 years". 
  200. ^ "Everest 2014: Season Summary – A Nepal Tragedy". Alanarnette.com. Retrieved 17 June 2016. 
  201. ^ "Kathmandu Post- 27 mountaineers, including 13 Nepalis, scale Mt Everest". 
  202. ^ a b c "After 2 deaths, 30 others frostbitten or sick on Everest". The Times of India (22 May 2016). Retrieved 22 May 2016. 
  203. ^ a b "Medical complications cut Everest research expedition short". Science | AAAS. 17 May 2016. Retrieved 25 May 2016. 
  204. ^ Agard, Chancellor (19 May 2016). "Peaople.com - Two Mount Everest Climbers Are Documenting Their Entire Journey on Snapchat in the First Ever Snap-umentary". People.com. Retrieved 17 June 2016. 
  205. ^ Manesh Shrestha. "Mount Everest gets 3G mobile network". CNN.com. Retrieved 17 June 2016. 
  206. ^ a b c "Everest explorers: Trash, bad behavior threaten mountain". WFAA.com. 7 June 2016. Retrieved 17 June 2016. 
  207. ^ a b "NTERVIEW: Melissa Arnot on Climbing Everest Without Supplemental Oxygen 06-Jun-2016 By Seth Heller". Rockandice.com. 6 June 2016. Retrieved 17 June 2016. 
  208. ^ Neil Tweedie (2 May 2007). "Peace at last for Sleeping Beauty". Telegraph. Retrieved 17 June 2016. 
  209. ^ a b c Mark Jenkins. "The last frontier: the climbers conquering Mount Everest without oxygen". Theguardian.com. Retrieved 17 June 2016. 
  210. ^ a b "Mount Everest Medical Station". BaseCampMD. Retrieved 17 June 2016. 
  211. ^ a b O'Neil, Devon (14 March 2013). "Climbing's Little Helper". Outside Online. Retrieved 17 June 2016. 
  212. ^ a b "Bill Burke, 69, arrives at base camp before north-route Everest climb". GrindTV.com. 12 April 2011. Retrieved 17 June 2016. 
  213. ^ Billera, Michael (17 February 2010). "Three Climbers Reported Dead Scaling Mount Everest: Eberhard Schaaf, Shriya Shah, and Song Won-bin Dead, Two Others Missing". Ibtimes.com. Retrieved 17 June 2016. 
  214. ^ Chris Graham (31 May 2016). "'It breaks my heart': Australian climber blames himself for wife's death on Everest". Telegraph.co.uk. Retrieved 17 June 2016. 
  215. ^ "UIAA OFFICIAL STANDARDS OF THE UIAA MEDICAL COMMISSION. VOL: 22a". Docplayer.net. Retrieved 17 June 2016. 
  216. ^ a b c d "Well under drugs is half way up? - Mount Everest - Adventure Sports - DW.COM". Blogs.dw.com. Retrieved 17 June 2016. 
  217. ^ Bob Condotta (8 June 2016). "Top of the world! Fan takes love of Seahawks to summit of Mount Everest". The Seattle Times. Retrieved 17 June 2016. 
  218. ^ "2 Brits, Mexican are 1st foreigners on Everest in 2 years". Seattletimes.com. 11 May 2016. Retrieved 17 June 2016. 
  219. ^ Liz Gelardi (6 June 2016). "Colorado woman checks Mount Everest off list on quest to climb "seven summits" - 7NEWS Denver". Thedenverchannel.com. Retrieved 17 June 2016. 
  220. ^ [13]
  221. ^ a b c "Briton Leslie Binns abandons Everest peak to save fellow climber - BBC News". Bbc.com. Retrieved 17 June 2016. 
  222. ^ "2016 Everest Expedition Nepal". International Mountain Guides. Retrieved 20 May 2016. 
  223. ^ a b Mizzima (20 May 2016). "Myanmar climbers reach Everest summit in country first". Mizzima. Retrieved 25 May 2016. 
  224. ^ a b "For the first time Tunisian climber reaches Everest peak - General news - ANSAMed.it". Ansamed.info. 19 December 2014. Retrieved 17 June 2016. 
  225. ^ a b "Alyssa Azar welcomed home at Toowoomba after climbing Mount Everest - ABC News (Australian Broadcasting Corporation)". Abc.net.au. 7 June 2016. Retrieved 17 June 2016. 
  226. ^ "1st Thai Mount Everest woman summiter meets PM Prayut - Thailand News - Thailand Forum". Thaivisa.com. Retrieved 17 June 2016. 
  227. ^ "First Thai woman conquers Mount Everest today | Coconuts Bangkok". Bangkok.coconuts.co. 23 May 2016. Retrieved 17 June 2016. 
  228. ^ Harry Yorke; Sophie Jamieson (17 May 2016). "British man becomes first person with cystic fibrosis to climb Everest". Telegraph.co.uk. Retrieved 17 June 2016. 
  229. ^ a b [14]
  230. ^ a b [15]
  231. ^ "Indian climber third to die on Mount Everest in recent days". Spokesman.com. Retrieved 25 May 2016. 
  232. ^ Chan, Melissa. "Woman Trying to Prove 'Vegans Can Do Anything' Dies on Mount Everest". TIME.com. Retrieved 25 May 2016. 
  233. ^ a b c Marszal, Andrew (25 May 2016). "Mount Everest climbers: Death toll rises to five". The Telegraph. Retrieved 25 May 2016. 
  234. ^ Emma McIntosh (3 June 2016). "Calgary doctor dies at Everest base camp". Calgary Herald. Retrieved 17 June 2016. 
  235. ^ a b Dunn, James (3 June 2016). "Mount Everest British climber Leslie Binns turns back just 500m from top to help stranger | Daily Mail Online". Dailymail.co.uk. Retrieved 17 June 2016. 
  236. ^ a b "Charles MacAdams Obituary - Calgary, AB | The Vancouver Sun". Legacy.com. Retrieved 17 June 2016. 
  237. ^ a b "3 climbers die in 3 days on Mount Everest". fox13now.com. 22 May 2016. Retrieved 17 June 2016. 
  238. ^ a b c d e f Andrew Marszal (25 May 2016). "Mount Everest climbers: Death toll rises to five". Telegraph.co.uk. Retrieved 17 June 2016. 
  239. ^ "Metres away from Mt Everest summit, Briton turns around to save Bengali woman | india-news". Hindustan Times. 2 June 2016. Retrieved 17 June 2016. 
  240. ^ a b "Back from Everest, Kolkata's frostbitten survivor plans her next climb". The Indian Express. 30 May 2016. Retrieved 17 June 2016. 
  241. ^ a b Sangam Prasain. "Kathmandu Post- Everest permits to be extended". Kathmandupost.ekantipur.com. Retrieved 17 June 2016. 
  242. ^ a b c "Everest permits: Climbers want Nepal 'to honour 2014 promise' - BBC News". Bbc.com. Retrieved 17 June 2016. 
  243. ^ a b "Ascent Routes on Everest". EverestHistory.com. Retrieved 21 January 2008. 
  244. ^ Thompson, Kalee (2 April 2003). "Everest Time Line: 80 Years of Triumph and Tragedy". National Geographic Society. Retrieved 28 March 2008. 
  245. ^ "Climbing Mount Everest". The New York Times. 19 May 1997. Retrieved 24 October 2008. 
  246. ^ Team Everest 03. "Mt. Everest Information". Retrieved 24 October 2008. 
  247. ^ Muza, SR; Fulco, CS; Cymerman, A (2004). "Altitude Acclimatization Guide.". US Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report (USARIEM–TN–04–05). Retrieved 5 March 2009. 
  248. ^ a b c d "The Way to the Summit". NOVA Online. Public Broadcasting Corporation. 2000. Retrieved 28 March 2008. 
  249. ^ "Chinese ladder". AFFIMER. 
  250. ^ "The Way to the Summit (North)". NOVA Online. Public Broadcasting Corporation. 2000. Retrieved 28 March 2008. 
  251. ^ "Swindon explorer on top of the world". Swindon Advertiser. Retrieved 20 September 2015. 
  252. ^ "Highest Mountain - Everest". extremescience.com. Retrieved 20 September 2015. 
  253. ^ "Montana State University - Everest Education Expedition - Everest Facts". Montana.edu. Retrieved 17 June 2016. 
  254. ^ "Everest Facts". Archived from the original on 9 May 2015. 
  255. ^ "Online high altitude oxygen calculator". altitude.org. Retrieved 15 August 2007. 
  256. ^ "Mount Everest South Col Route Maps". alanarnette.com. Retrieved 15 August 2013. 
  257. ^ Grocott, Michael P.W.; et al. (2009). "Arterial Blood Gases and Oxygen Content in Climbers on Mount Everest" (PDF). The New England Journal of Medicine. 360 (2): 140–9. doi:10.1056/NEJMoa0801581. PMID 19129527. 
  258. ^ "Everest 2007". Caudwell Xtreme Everest 2007. Archived from the original on 6 June 2008. 
  259. ^ "Altitude physiology". altitude.org. Retrieved 6 July 2010. 
  260. ^ Levett, Connie (3 June 2006). "The deadly business of climbing Everest". The Age. Melbourne. 
  261. ^ "Mortality on Mount Everest, 1921-2006: descriptive study". bmj.com. Retrieved 20 September 2015. 
  262. ^ "CLIMBING EVEREST: WHO MAKES IT TO THE TOP?". Climbing. Retrieved 20 September 2015. 
  263. ^ Svati Kirsten Narula. "Charting Deaths on Mount Everest". The Atlantic. Retrieved 20 September 2015. 
  264. ^ a b "The Top Ten Most Extreme Sports in the World". TheRichest. Retrieved 20 September 2015. 
  265. ^ a b "Everest Base Jumper". Red Bull. 
  266. ^ a b "5 Mountains Deadlier Than Everest". Mental Floss. Retrieved 20 September 2015. 
  267. ^ a b "Everest anniversary: World's five deadliest mountains". Yahoo News UK. 28 May 2013. Retrieved 20 September 2015. 
  268. ^ a b c "Everest team forced to leave sick British climber to die". The Independent. Retrieved 20 September 2015. 
  269. ^ a b Peter Gillman (2 June 2010). "What killed Peter Kinloch, 'left to die' on Everest | The Week UK". Theweek.co.uk. Retrieved 17 June 2016. 
  270. ^ a b c d "Paragliding From Everest's Peak, Then Kayaking to Indian Ocean - ABC News". Abcnews.go.com. 5 December 2013. Retrieved 17 June 2016. 
  271. ^ "Chamber of Horrors: The Oxygen Mask". MountainZone.com. 21 May 1998. Archived from the original on 22 August 2000. Retrieved 1 April 2007. 
  272. ^ "Field Test on Everest: To Os or not to Os". National Geographic. 18 May 2012. Retrieved 11 May 2015. 
  273. ^ a b "Brain Hypoxia". Healthline. 25 July 2012. Retrieved 20 September 2015. 
  274. ^ "Dementia From Oxygen Deprivation". Dementia.org. Retrieved 20 September 2015. 
  275. ^ a b "The high-altitude brain". biologists.org. Retrieved 20 September 2015. 
  276. ^ Tom Holzel; Audrey Salkeld (1986). The Mystery of Mallory & Irvine. 
  277. ^ Hunt, John (1953). "Appendix VII". The Ascent of Everest. Hodder & Stoughton. 
  278. ^ Krakauer (1997), p. 154
  279. ^ DeWalt, Weston (7 August 1998). "Everest controversy continues". Wanderlust. salon.com. Archived from the original on 14 May 2011. Retrieved 17 June 2016. 
  280. ^ "The Oxygen Illusion". The Anatoli Boukreev Memorial Fund. Retrieved 24 June 2010. 
  281. ^ a b Garner, Dwight (August 1998). "Coming Down". Salon.com. p. 3. Archived from the original on 3 March 2000. 
  282. ^ Boukreev, Anatoli; DeWalt, Weston (1998). The Climb. St. Martins Paperbacks. p. 182. ISBN 0-312-96533-8. 
  283. ^ a b c "This is your brain. This is your brain at altitude.". boulderweekly.com. Retrieved 20 September 2015. 
  284. ^ a b "The Kathmandu Post :: Read the Post. Get Posted.". ekantipur.com. Archived from the original on 21 July 2015. Retrieved 20 September 2015. 
  285. ^ K.S. Gulia (1 January 2007). Discovering Himalaya : Tourism Of Himalayan Region (2 Vols.). Gyan Publishing House. p. 34. ISBN 978-81-8205-410-3. 
  286. ^ "Window of Opportunity: Everest Climbing Season Underway". AccuWeather. Retrieved 20 September 2015. 
  287. ^ "Japanese summits". Everest History.com. 
  288. ^ "U.S. Climber Chris Chandler Dies on Nepal Peak". latimes. Retrieved 20 September 2015. 
  289. ^ "Asia, Nepal, Malahangur Asia, Nepal (Khumbu), Everest, Summer and Autumn Attempts with Ski and Snowboard - AAC Publications - Search The American Alpine Journal and Accidents In North American Mountaineering". americanalpineclub.org. Retrieved 20 September 2015. 
  290. ^ Huey, RB; Salisbury, R (2003). "Success & death on Everest" (PDF). American Alpine Journal. 
  291. ^ "Radiation exposures of aircrew in high altitude flight - IOPscience". Iopscience.iop.org. 26 February 2015. doi:10.1088/0952-4746/21/1/003. Retrieved 17 June 2016. 
  292. ^ "Nepal to cut fees for off-season Everest climbers". Reuters. Retrieved 20 September 2015. 
  293. ^ "George Finch". Retrieved 18 April 2013. 
  294. ^ a b Victoria, James (27 May 2012). "Japan's Everest timeline". Japan Times. 
  295. ^ Reinhold Messner (15 November 2014). Everest: Expedition to the Ultimate. Vertebrate Graphics Limited. p. 283. ISBN 978-1-910240-21-2. 
  296. ^ John B West (27 May 2013). High Life: A History of High-Altitude Physiology and Medicine. Springer. p. 487. ISBN 978-1-4614-7573-6. 
  297. ^ "Pāndēng zhū fēng chuánqí" 攀登珠峰传奇 [Everest Legend] (in Chinese). People's Daily. 
  298. ^ a b "Everest – First without oxygen". NOVA Online. PBS. 2000. Retrieved 28 March 2008. 
  299. ^ "A view from the top of the world". BBC News. 15 February 2007. Retrieved 6 October 2010. 
  300. ^ "Firsts". Everest History.com. Retrieved 8 February 2014. 
  301. ^ "Sherpa Attempts Everest Speed Climbing Record". Classic.mountainzone.com. Archived from the original on 16 November 2012. Retrieved 24 October 2012. 
  302. ^ "New/Old Records Record". everestsummiteersassociation.org. Retrieved 30 April 2013. 
  303. ^ 1999 American Alpine Journal. American Alpine Club Press. p. 374. ISBN 978-1-933056-46-3. Retrieved 25 April 2015. 
  304. ^ Stuart, Julia (10 October 2000). "The man who skied down Everest". The Independent. London. Archived from the original on 22 June 2013. 
  305. ^ Greenfeld, Karl (18 June 2001). "Adventure: Blind To Failure". Time Magazine. Retrieved 7 May 2013. 
  306. ^ "SAWNET: Who's Who: Lhakpa Sherpa". 
  307. ^ "Sherpa sets record Everest time". BBC News. 21 May 2004. 
  308. ^ Grayson Schaffer. "The Most Successful Female Everest Climber of All Time Is a Housekeeper in Hartford, Connecticut". Outside Online. 
  309. ^ "58 Stunden, 45 Minuten". Süddeutsche Zeitung (in German). 10 December 2007. 
  310. ^ "In 16 Stunden auf den Mount Everest" [In 16 hours to Mount Everest] (in German). bergsteigen.com. 30 May 2006. Retrieved 16 June 2016. 
  311. ^ "Everest K2 News Explorersweb – the pioneers checkpoint". Explorersweb.com. 21 May 2010. Retrieved 22 August 2010. 
  312. ^ a b c "Nepal's 'Super Sherpa' breaks his own Everest record". BBC News. 11 May 2011. Retrieved 15 May 2012. 
  313. ^ O'Neil, Devon (14 November 2013). "espnW - Melissa Arnot has conquered Mount Everest five times, but American is hailed as hero for playing peacemaker on mountain's slopes". Espn.go.com. Retrieved 17 June 2016. 
  314. ^ "Canadian double-amputee summits Mount Everest". 31 May 2013. 
  315. ^ "Teen with Down syndrome becomes first ever to reach Mt. Everest base camp". Fox News. Retrieved 20 September 2015. 
  316. ^ a b "A view from the top of the world". BBC News. 15 February 2007. Retrieved 6 October 2010. 
  317. ^ a b Harlin, John (May 1989). "Get Down". Backpacker Magazine: 11. 
  318. ^ a b "Hang glider and Paraglider expeditions to Everest". flymicro.com. Retrieved 2 October 2010. 
  319. ^ "BASE Fatality List - Jean-Marc Boivin". blincmagazine.com. 23 January 2016. Retrieved 17 June 2016. 
  320. ^ a b "A Hot-Air Balloon Ride Over Mt. Everest Will Cost You $2.6 Million". 
  321. ^ a b c "Andy Elson goes over the top.". andyelson.com. Archived from the original on 4 March 2016. Retrieved 20 September 2015. 
  322. ^ "Spectacular panorama captured of the Himalayas from hot air balloon". Telegraph.co.uk. 22 July 2009. Retrieved 20 September 2015. 
  323. ^ a b c "Landing on Air". National Geographic Adventure. 1 September 2005. Retrieved 24 June 2009. 
  324. ^ a b "Rotorcraft World Records". FAI. Archived from the original on 2 December 2008. 
  325. ^ "French Everest Mystery Chopper's Utopia summit". MountEverest.net. 27 May 2005. 
  326. ^ a b c "Sano Babu Sunuwar and Lakpa Tsheri Sherpa, Adventurers of the Year 2012 - National Geographic". Adventure.nationalgeographic.com. 1 January 1970. Retrieved 17 June 2016. 
  327. ^ "Ultimate Descent: Paragliding off Everest Video - ABC News". Abcnews.go.com. Retrieved 17 June 2016. 
  328. ^ Sharma, Gopal (27 May 2014). "Nepal probes if Chinese woman used helicopter on Everest climb". Reuters. Retrieved 17 June 2016. 
  329. ^ a b "Chinese Woman Becomes First to Summit Everest After Avalanche". News.nationalgeographic.com. Retrieved 17 June 2016. 
  330. ^ a b c "Helicopter transport flights to Everest high camps - Mount Everest - Adventure Sports - DW.COM". Blogs.dw.com. 25 April 2015. Retrieved 17 June 2016. 
  331. ^ Bergqvist, Pia. "Bell Helicopter Tests 412EPI Near Mount Everest | Flying Magazine". Flyingmag.com. Retrieved 17 June 2016. 
  332. ^ "Kenton Cool: my journey from a wheelchair to the peak of Mount Everest". Telegraph.co.uk. 11 August 2015. Retrieved 20 September 2015. 
  333. ^ a b c Duncan Chessell. "Manny Pizarro robbed and abandoned by Sherpa after summiting Everest - being helped down by DCXP's sirdar". 
  334. ^ Jason Burke. "Mount Everest to be declared off-limits to inexperienced climbers, says Nepal". Theguardian.com. Retrieved 17 June 2016. 
  335. ^ a b c d e "Mt Everest 'summit fever': Why climbers make poor decisions near peak". heraldsun.com.au. 28 May 2016. Retrieved 17 June 2016. 
  336. ^ a b David Chazan (28 July 2014). "Mont Blanc officials condemn 'stupidity' of tourist climbers as Irishman falls to death". Telegraph. Retrieved 17 June 2016. 
  337. ^ "Why Is Mont Blanc One of the World's Deadliest Mountains?". The Atlantic. 25 July 2012. Retrieved 17 June 2016. 
  338. ^ "Nepal - Gokyo valley and Everest Base Camp trek". 
  339. ^ "Nepal". Developing World Connections. 25 April 2015. Retrieved 17 June 2016. 
  340. ^ Conger, Cristen (1 April 2008). "How has Mount Everest tourism affected Nepal? | HowStuffWorks". Adventure.howstuffworks.com. Retrieved 17 June 2016. 
  341. ^ "Fixed ropes". 
  342. ^ "What It Costs To Climb Mount Everest". 
  343. ^ "The Physical Demands of Climbing Denali" (PDF). 
  344. ^ Stall, Bill (2 May 1985). "Conquers Mt. Everest to Fulfill Dream: Millionaire First to Climb Summits of All Continents". Los Angeles Times. 
  345. ^ Krakauer (1997), pp. 24, 42
  346. ^ "Everest's decline blamed on trail of rich tourists". The Guardian. London. 
  347. ^ "Home on the range". The Guardian. London. 
  348. ^ "Sir Edmund Hillary: The Right Stuff". 
  349. ^ "Hillary laments Everest changes". BBC News. 26 May 2003. 
  350. ^ "Interview with Sir Edmund Hillary". Foreign Correspondent. ABC. 29 April 2003. Retrieved 26 April 2014. 
  351. ^ a b James Clash (12 November 2003). "The Adventurer: Dick Bass' Many Summits". Forbes. Retrieved 20 September 2015. 
  352. ^ "Everest fatality silence mystery solved: British David Sharp left to die by 40 climbers". Explorersweb. 
  353. ^ "Brazilian Vitor Negrete lost on Everest after a no O2 summit". Explorersweb. 
  354. ^ "Guest Insights: A leadership nightmare turned Everest triumph - Anne Parmenter". washingtonpost.com. Retrieved 20 September 2015. 
  355. ^ Kodas, Michael (2008). High Crimes: The Fate of Everest in an Age of Greed. Hyperion. ISBN 9781401302733. 
  356. ^ "Go Sell It on the Mountain". Mother Jones. 1 February 2008. 
  357. ^ Bristow, Michael (13 July 2007). "Everest base camp a 'wild-west town'". BBC News. Retrieved 31 March 2010. 
  358. ^ a b c McCarthy, Julie (24 April 2014). "Sherpas Walk Off The Job After Deadly Avalanche". NPR. Retrieved 26 April 2014. 
  359. ^ "Sherpas Consider Boycott After Everest Disaster". NPR. Associated Press. 21 April 2014. Archived from the original on 21 April 2014. Retrieved 26 April 2014. 
  360. ^ a b "Mount Everest Snowboard Controversy Solved". TransWorld SNOWboarding. 27 June 2001. Retrieved 20 September 2015. 
  361. ^ "Skiing Down Mount Everest and the World's Highest Peaks". igluski.com. Retrieved 17 June 2016. 
  362. ^ Salisbury, Richard (2004). The Himalayan database the expedition archives of Elizabeth Hawley. Golden, Colo.: American Alphine Club Press. ISBN 0930410998. 
  363. ^ "Tomas Olsson found dead - Skiing down from the North side of Mount Everest ended in tradegy!". travelexplorations.com. Retrieved 20 September 2015. 
  364. ^ Walt Unsworth (2000). Everest: The Mountaineering History. London, UK: Mountaineers. p. 626. ISBN 978-0-89886-670-4. 
  365. ^ Sano Babu Sunuwar & Lakpa Tsheri Sherpa. "Ultimate Adventure Bucket List - Dream Trip: Make the Ultimate Descent -- National Geographic". National Geographic. Retrieved 20 September 2015. 
  366. ^ Cooper, Tarquin (28 May 2013). "Valery Rozov BASE Jumps From Mt Everest". Red Bull. 
  367. ^ a b c Coburn, Broughton. "Mount Everest Fight Raises Questions About Sherpas". National Geographic (magazine). Retrieved 14 September 2013. 
  368. ^ Gilbert, Jeanne-Marie. "Rongbuk Monastery". PBS. Retrieved 14 September 2013. 
  369. ^ "We preserve Everest". Mt. Everest Biogas Project. Retrieved 28 June 2016. 
  370. ^ a b [16]
  371. ^ Sherpa, Phurba (28 May 2016). "Mount Everest death toll rises to five". CNN.com. Retrieved 17 June 2016. 
  372. ^ "5 Everest facts". historyextra.com. Retrieved 1 June 2016. 
  373. ^ H. P. S. Ahluwalia (1978). Faces of Everest. Vikas Publishing House. ISBN 978-0-7069-0563-2. 

Further reading

For 1924 Mount Everest expedition, see 1924 British Mount Everest expedition § Bibliography.
For first ascent of Mount Everest, see 1953 British Mount Everest expedition § Further reading.

External links

External images
360° panoramic view (virtual tour)