Cascade Range

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"Cascades" redirects here. For other uses, see Cascades (disambiguation).

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Cascade Range-related plate tectonics

The Cascade Range (or Cascades) is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades. The small part of the range in British Columbia is referred to as the Canadian Cascades or, locally, as the Cascade Mountains. The latter term is also sometimes used by Washington residents to refer to the Washington section of the Cascades in addition to North Cascades, the more usual American term, as in North Cascades National Park.

The Cascades are part of the Pacific Ring of Fire, the ring of volcanoes and associated mountains around the Pacific Ocean. All of the known historic eruptions in the contiguous United States have been from Cascade volcanoes. The two most recent were Lassen Peak in 1914 to 1921 and a major eruption of Mount St. Helens in 1980. Minor eruptions of Mount St. Helens have also occurred since, most recently in 2006.[1]

Geography

Map of the Cascade Range showing major volcanic peaks.

The Cascades extend from Lassen Peak (also known as Mount Lassen) (3170 m) in northern California to the confluence of the Nicola and Thompson Rivers in British Columbia. The Fraser River separates the Cascades from the Coast Mountains.[2] The tallest volcanoes of the Cascades are called the High Cascades and dominate their surroundings, often standing twice the height of the nearby mountains. They often have a visual height (height above nearby crestlines) of one mile (1.6 km) or more. The tallest peaks, such as the 14,411 foot (4,395 m) high Mount Rainier, dominate their surroundings for 50 to 100 miles (80 to 160 km).

The northern part of the range, north of Mount Rainier, is known as the North Cascades in the United States but is formally named the Cascade Mountains north of the Canada – United States border, reaching to the northern extremity of the Cascades at Lytton Mountain. Overall, the North Cascades and southwestern Canadian Cascades are extremely rugged, with many of the lesser peaks steep and glaciated, with valleys quite low relative to its peaks and ridges, resulting in great local relief, and major passes are only about 1,000 m (3,300 ft) high. The southern part of the Canadian Cascades, particularly the Skagit Range, is geologically and topographically similar to the North Cascades, while the northern and northeastern parts - the Coquihalla Range, the name of which is unofficial,[citation needed], the northern half of the Hozameen Range and most of the Okanagan Range are less glaciated and more plateau-like in character, resembling nearby areas of the Thompson Plateau.

Because of the range's proximity to the Pacific Ocean and the region's prevailing westerly winds, precipitation is substantial, especially on the western slopes, with annual accumulations of up to 150 inches (3,800 mm) in some areas—Mount Baker, for instance, recorded the largest single-season snowfall on record in the world in 1999—and heavy snowfall as low as 2,000 feet (600 m). It is not uncommon for some places in the Cascades to have over 200 inches (5,500 mm) of snow accumulation, such as at Lake Helen (near Lassen Peak), one of the snowiest places in the world. Most of the High Cascades are therefore white with snow and ice year-round. The western slopes are densely covered with Douglas-fir, Western Hemlock and Red alder, while the drier eastern slopes are mostly Ponderosa Pine, with Western Larch at higher elevations. Annual rainfall drops to 9 inches (200 mm) on the eastern foothills due to a rainshadow effect.

Beyond the foothills is an arid plateau that was created 16 million years ago as a coalescing series of layered flood basalt flows. Together, these sequences of fluid volcanic rock form a 200,000 sq mi (520,000 km2) region out of eastern Washington, Oregon, and parts of Northern California and Idaho called the Columbia River Plateau.

The Columbia River Gorge is the only major break in the American part of the Cascades. When the Cascades started to rise 7 million years ago in the Pliocene, the Columbia River drained the relatively low Columbia River Plateau. As the range grew, the Columbia was able to keep pace, creating the gorge and major pass seen today. The gorge also exposes uplifted and warped layers of basalt from the plateau.

History

Cascade eruptions in the last 4000 years

Indigenous peoples have inhabited the area for thousands of years and developed their own myths and legends concerning the Cascades. According to some of these tales, Mounts Baker, Jefferson, and Shasta were used as refuge from a great flood. Other stories, such as the Bridge of the Gods tale, had various High Cascades such as Hood and Adams, act as god-like chiefs who made war by throwing fire and stone at each other. St. Helens with its pre-1980 graceful appearance, was regaled as a beautiful maiden for whom Hood and Adams feuded. Among the many stories concerning Mount Baker, one tells that the mountain was formerly married to Mount Rainier and lived in that vicinity. Then, because of a marital dispute, she picked herself up and marched north to her present position. Native tribes also developed their own names for the High Cascades and many of the smaller peaks, the most well known to non-natives being Tahoma, the Lushootseed name for Mount Rainier.

In the spring of 1792 British navigator George Vancouver entered Puget Sound and started to give English names to the high mountains he saw. Mount Baker was named for Vancouver's third lieutenant, the graceful Mount St. Helens for a famous diplomat, Mount Hood was named in honor of Samuel Hood, 1st Viscount Hood (an admiral of the Royal Navy) and the tallest Cascade, Mount Rainier, is the namesake of Admiral Peter Rainier. Vancouver's expedition did not, however, name the range these peaks belonged to. As marine trade in the Strait of Georgia and Puget Sound proceeded in the 1790s and beyond, the summits of Rainier and Baker became familiar to captains and crews (mostly British and American over all others, but not exclusively).

In 1805 the Lewis and Clark Expedition passed through the Cascades by using the Columbia River, which for many years was the only practical way to pass that part of the range. Trade on the lower Columbia River did not occur until after Lewis and Clark in 1806, more specifically as a result of David Thompson's visit on behalf of the North West Company shortly afterwards, and Simon Fraser's journey down the Fraser in 1808. The Lewis and Clark expedition, and the many settlers and traders that followed, met their last obstacle to their journey at the Cascades Rapids in the Columbia River Gorge, a feature on the river now submerged beneath the Bonneville Reservoir. Before long, the great white-capped mountains that loomed above the rapids were called the "mountains by the cascades" and later simply as the "Cascades". The earliest attested use of the name "Cascade Range" is in the writings of botanist David Douglas.[3] On their return trip Lewis and Clark's group spotted a high but distant snowy pinnacle that they named for the sponsor of the expedition, U.S. President Thomas Jefferson.

Mount Rainier, with Tacoma, Washington in foreground
Central Washington Cascades

In 1814 Alexander Ross, a fur trader with the North West Company, seeking a viable route across the mountains, explored and crossed the northern Cascades between Fort Okanogan and Puget Sound. His report of the journey is vague about the route taken. He followed the lower Methow River into the mountains. He might have used Cascade Pass to reach the Skagit River. Ross was the first European-American to explore the Methow River area and likely the first to explore the Stehekin River and Bridge Creek region. Due to the difficulty of crossing the northern Cascades and the paucity of beaver, after Ross fur-trading companies made only a few explorations into the mountains north of the Columbia River after Ross.[4]

Exploration and settlement of the Cascades region by Europeans and Americans was accelerated by the establishment of a major trading post of the Hudson's Bay Company at Fort Vancouver near today's Portland, Oregon. From this base, Hudson's Bay Company trapping parties traveled throughout the Cascades in search of beaver and other fur-bearing animals. For example, using what became known as the Siskiyou Trail, Hudson's Bay Company trappers were the first non-natives to explore the southern Cascades in the 1820s and 1830s, establishing trails which passed near Crater Lake, Mount McLoughlin, Medicine Lake Volcano, Mount Shasta, and Lassen Peak.

The course of political history in the Pacific Northwest saw the spine of the Cascade Range being proposed as a boundary settlement during the Oregon Dispute of 1846. The United States rejected the proposal and insisted on the 49th parallel north, which cuts across the range just north of Mount Baker. Throughout the period of dispute and up to the creation of the Crown Colony of British Columbia in 1858, the Hudson's Bay Company's York Factory Express route, as well the route of fur brigades, followed the Okanogan River along the east edge of the Cascades and the Columbia River through the range. Passes across the range were not well known and little used. Naches Pass was used for driving cattle and horses to Fort Nisqually. Yakima Pass was also used by the Hudson's Bay Company.[5] The vast majority of non-native residents of the Cascade Range region until about 1840 were British subjects, most of mixed French-native blood and some Hawaiians and blacks as well as Scots who were the backbone of Hudson's Bay Company administration.

American settlement of the flanks of the Coast Range did not occur until the early 1840s, at first only marginally. Following the Oregon Treaty the inward flux of migration from the Oregon Trail intensified and the passes and back-valleys of what is now the state of Washington were explored and populated, and it was not long after that railways followed. Despite its being traversed by several major freeways and rail lines, and its lower flanks subjected to major logging in recent decades, large parts of the range remain intense and forbidding alpine wilderness. Most of the northern half of the High Cascades, from Rainier north, have been preserved by US national or British Columbia provincial parks (such as E.C. Manning Provincial Park), or other forms of protected area.

The Canadian side of the range has a history that includes the Fraser Canyon Gold Rush of 1858-60 and its famous Cariboo Road, as well as the older Hudson's Bay Company Brigade Trail from the Canyon to the Interior, the Dewdney Trail, and older routes which connected east to the Similkameen and Okanagan valleys.

The southern mainline of the Canadian Pacific Railway penetrated the range via the passes of the Coquihalla River, along one of the steepest and snowiest routes in the entire Pacific Cordillera. Near Hope, B.C., the railway roadbed and the Othello Tunnels, now decommissioned, are popular tourist recreation destinations for hiking and bicycling. The pass is used by the Coquihalla Highway, a government megaproject built as part of the Expo 86 spending boom of the 1980s, which is now the main route from the Coast to the British Columbia interior. Traffic formerly went via the Fraser Canyon, to the west, or via Allison Pass and Manning Park along Highway 3 to the south, near the border.

Mount Shasta from Siskiyou Trail
Lassen Peak in California

The Barlow Road was the first established land path for U.S. settlers through the Cascade Range in 1845, and formed the final overland link for the Oregon Trail (previously, settlers had to raft down the treacherous rapids of the Columbia River). The Barlow Road left the Columbia at Hood River and passed along the south side of Mount Hood at Government Camp, terminating in Oregon City. There is an interpretive site there now at "The End of The Oregon Trail." The road was constructed as a toll road — $5/wagon — and was very successful.

In addition, the Applegate Trail was created to allow settlers to avoid rafting down the Columbia River. The Applegate Trail used the path of the California Trail to north-central Nevada. From there, the Applegate Trail headed northwest into northern California, and continued northwest towards today's Ashland, Oregon. From there, settlers would head north along the established Siskiyou Trail into the Willamette Valley.

With the exception of the 1915 eruption of remote Lassen Peak in Northern California, the range was quiet for more than a century. Then, on May 18, 1980, the dramatic eruption of little-known Mount St. Helens shattered the quiet and brought the world's attention to the range. Geologists were also concerned that the St. Helens eruption was a sign that long-dormant Cascade volcanoes might become active once more, as in the period from 1800 to 1857 when a total of eight erupted. None have erupted since St. Helens, but precautions are being taken nevertheless, such as the Mount Rainier Volcano Lahar Warning System in Pierce County, Washington.[6]

Human uses

Soil conditions for farming are generally good, especially downwind of volcanoes. This is largely due to the fact that volcanic rocks are often rich in potassium bearing minerals such as Orthoclase and decay easily. Volcanic debris, especially lahars, also have a leveling effect and the storage of water in the form of snow and ice is also important. These snow capped mountains such as Mt. Hood and Mt.Bachelor are used as ski resorts in the late winter. Much of that water eventually flows into reservoirs where it is used for recreation before its potential energy is captured to generate hydroelectric power before being used to irrigate crops.

Because of the abundance of powerful streams, many of the major westward rivers off the Cascades have been dammed to provide hydroelectric power. One of these, Ross Dam on the Skagit River, created a reservoir which spans the border southeast of Hope, British Columbia, extending into Canada two miles (3 km). At the foot of the southeast flank of Mount Baker, at Concrete, Washington, the Baker River is dammed to form Lake Shannon and Baker Lake.

In addition, there is a largely untapped amount of geothermal power that can be generated from the Cascades. The USGS Geothermal Research Program has been investigating this potential. Some of this energy is already being used in places like Klamath Falls, Oregon where volcanic steam is used to heat public buildings.[citation needed] The highest recorded temperature found in the range is 510 °F (265 °C) at 3,075 feet (937 m) below Newberry Volcano's caldera floor.

Cascade Range volcanoes

Further information: Cascade Volcanoes
Mount BakerGlacier PeakMount RainierMount St. HelensMount St. HelensMount AdamsMount HoodMount JeffersonThree SistersNewberry VolcanoMount Mazama (Crater Lake National Park)Mount McLoughlinMedicine Lake VolcanoMount ShastaMount ShastaLassen Peak
Major volcanoes in the Cascade Range (image map)

Volcanoes south of the Fraser River in the Cascade Volcanic Arc (a geological term) belong to the Cascade Range (a geographic term). Peaks are listed north to south.

North Cascades

  • Coquihalla Mountain (southern British Columbia) — highest peak in the Bedded Range.
  • Mount Baker (Near the United States-Canada border) — highest peak in northern Washington. It is an active volcano.[7] Steam activity from its crater occurs relatively frequently. Mount Baker is one of the snowiest places on Earth; in 1999 the ski area (on a subsidiary peak) recorded the world's greatest single-season snowfall: 1,140 inches (95 feet or 2,896 cm).
  • Glacier Peak (northern Washington) — secluded and relatively inaccessible peak. Contrary to its name, its glacial cover is not that extensive. The volcano is surprisingly small in volume, and gets most of its height by having grown atop a nonvolcanic ridge.

High Cascades

  • Mount Rainier (southeast of Tacoma, Washington) — highest peak in the Cascades, it dominates the surrounding landscape. There is no other higher peak northward until the Yukon-Alaska-BC border apex beyond the Alsek River.
  • Mount St. Helens (southern Washington) — Erupted in 1980, leveling forests to the north of the mountain and sending ash across the northwest. The northern part of the mountain was destroyed in the blast (1980 Mount St. Helens eruption).
  • Mount Adams (east of Mount St. Helens) — the second highest peak in Washington and third highest in the Cascade Range.
  • Mount Hood (northern Oregon) — the highest peak in Oregon and arguably the most frequently climbed major peak in the Cascades.
  • Mount Jefferson (northcentral Oregon) — the second highest peak in Oregon.
  • Three Fingered Jack (northcentral Oregon) — Highly eroded Pleistocene volcano.
  • Mount Washington (between Santiam and McKenzie passes) — a highly eroded shield volcano. [8]
  • Three Sisters (near the city of Bend, Oregon) — South Sister is the highest and youngest, with a well-defined crater. Middle Sister is more pyramidal and eroded. North Sister is the oldest and has a crumbling rock pinnacle.
  • Broken Top (to the southeast of South Sister) — a highly eroded extinct stratovolcano. Contains Bend Glacier.
  • Newberry Volcano — isolated caldera with two crater lakes. Very variable lavas. Flows from here have reached the city of Bend.
  • Mount Bachelor (near Three Sisters) — a geologically young (less than 15,000 years) shield-to-stratovolcano which is now the site of a popular ski resort. (Mt. Bachelor ski area)
  • Diamond Peak (south of Willamette Pass)  — a 8,744 feet (2,665 m) volcano composed of 15 cubic kilometres (3.6 cu mi) of basaltic andesite.
  • Mount Bailey (north of Mount Mazama)
  • Mount Thielsen (east of Mount Bailey) — highly eroded volcano with a prominent spire, making it the Lightning Rod of the Cascades.
  • Mount Mazama (southern Oregon) — better known for its Crater Lake, which is a caldera formed by a catastrophic eruption which took out most of the summit roughly 6,900 years ago. Mount Mazama is estimated to have been about 11,000 ft. (3,350 m) elevation prior to the blast.
  • Mount Scott (southern Oregon) — on the southeastern flank of Crater Lake. At 8,929 feet (2,721 m) elevation, this small stratovolcano is the highest peak in Crater Lake National Park.
  • Mount McLoughlin (near Klamath Falls, Oregon) — presents a symmetrical appearance when viewed from Klamath Lake.
  • Medicine Lake Volcano — a shield volcano in northern California which is the largest volcano by volume in the Cascades.
  • Mount Shasta (northern California) — second highest peak in the Cascades. Can be seen in the Sacramento Valley as far as 140 miles (225 km) away, as it is a dominating feature of the region.
  • Lassen Peak (south of Mount Shasta) — southernmost volcano in the Cascades and the most easily climbed peak in the Cascades. It erupted from 1914 to 1921, and like Mount Shasta, it too can be seen in the Sacramento Valley, up to 120 miles (193 km) away. Lowest Peak because the Cascades extend from it.
Picture of Mount Bachelor, Broken Top and the Three Sisters
Mt. Bachelor, Broken Top, and The Three Sisters.

Protected areas

Three Fingered Jack and Santiam Pass, Oregon

There are four U.S. National Parks in the Cascade Range, one National Scenic Area, and many U.S. National Monuments, U.S. Wilderness Areas, and U.S. National Forests. Each classification protects the various glaciers, volcanoes, geothermal fields, rivers, lakes, forests, and wildlife to varying degrees.

National parks

National Scenic Areas

National monuments

Provincial Parks

Wilderness areas

Ecology

Oval-leaf Blueberry on Mount Pilchuck
Main articles: Cascades (ecoregion) and Ecology of the North Cascades

There is a wide range of flora and fauna inhabiting the Cascade Range. The southern part of the Cascades are within what Conservation International defines as the California Floristic Province, an area of high biodiversity.

Black bears, coyotes, bobcats, cougars, Beavers, deer, and elk live in the Cascades, and in the northern mountains, Grizzly bears.

Most of the Cascades' lower and middle elevations are covered in coniferous forest and temperate rainforest; the higher altitudes have areas of alpine tundra and glaciers. Common trees include Western hemlock and Douglas fir.

See also

Notes

  1. ^ "Mount St. Helens, Washington: Eruption 2004 to Current". United States Geological Survey. Retrieved February 1, 2008.
  2. ^ Beckey, Fred (2008). Cascade Alpine Guide: Climbing and High Routes Rainy Pass to Fraser River. The Mountaineers Books. pp. 191–194. ISBN 978-1-59485-136-0. Retrieved 27 November 2011.
  3. ^ Beckey, Fred (2003). Range of Glaciers: The Exploration and Survey of the Northern Cascade Range. Oregon Historical Society Press. p. 48. ISBN 0-87595-243-7.
  4. ^ Range of Glaciers, pp. 41-45.
  5. ^ Range of Glaciers, pp. 63-64, 98.
  6. ^ "Pilot Project - Mount Rainier Volcano Lahar Warning System". Volcano Hazards Program. USGS. Archived from the original on 2008-05-11.
  7. ^ Scott, Kevin M. (2005-05-25). Mount Baker-Living with an Active Volcano: U.S. Geological Survey Fact Sheet 059-00. United States Geological Survey. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  8. ^ "Mount Washington Wilderness, Willamette National Forest, Oregon". Wildernet.com.

References

External links

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