Bluff Knoll

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Bluff Knoll
Bluff knoll 01 gnangarra.jpg
Highest point
Elevation1,099 m (3,606 ft)[1]
Prominence650 m (2,130 ft)
Coordinates34°22′32″S 118°15′22″E / 34.37556°S 118.25611°E / -34.37556; 118.25611Coordinates: 34°22′32″S 118°15′22″E / 34.37556°S 118.25611°E / -34.37556; 118.25611[1]
Geography
Parent rangeStirling Range

Bluff Knoll is the highest peak of the Stirling Range in the Great Southern region of Western Australia (WA). It is 1,099 metres (3,606 ft) above sea level, with a prominence of 650 m (2,130 ft).[1] The local Aboriginal people, the Mineng and Koreng/Goreng sub-groups of the Noongar Nation, call the mountain Boola Miyel or Pualaar Miial, meaning "great many-faced hill"[2] or "many eyes", as the peak has rock formations that resemble eyes looking out across the valley.

The Bluff Knoll trail is a round trip of about 6 kilometres (4 mi) taking three to four hours,[3] and has a Grade 4 rating of climbing difficulty, with some steep and rough steps.[3] In 2020 many parts of the trail were destroyed in the Black Summer bushfires, and has since been upgraded and improved.[4] The view from the summit encompasses the Stirling and Porongurup mountain ranges, as well as the coast near Albany.

Due to its altitude, Bluff Knoll and the surrounding peaks of the Stirling Ranges are some of only a few places to experience regular snowfalls in Western Australia.[5] When snow is forecast by the Bureau of Meteorology it attracts hikers from all over the southwest region to experience it.

The peak was given its name by Governor James Stirling as the highest point in the Stirling Range.[6] Although Bluff Knoll is sometimes claimed to be the highest point in Western Australia,[6] the highest peak is actually Mount Meharry in Karijini National Park in the Hamersley Range, which is 1,249 metres (4,098 ft) above sea level.

Aboriginal History[edit]

Some Mineng and Koreng/Goreng people treat the bluff with foreboding and prefer to avoid its rocky ridges. Noongar artist Tjyllyungoo/Lance Chadd states:

"It's a place of different moods, lots of eyes looking...In the old days, old people went around that place. It holds the totemic spirit of our people."[2]

The mountain is often shrouded in a mist which curls around the peaks and floats into the gullies. Signage at the Bluff Knoll carpark states that a mist-like spirit named Noatch (meaning "dead body" or "corpse" in the Noongar language) resides there.[7] In 'Boola Miyel: The place of many faces' Noongar Elders Jack Williams and Averil Dean state:

"Boola Miyel is the place of many faces. If you look into the rock face you will see all of the eyes of the many faces looking out at you. Boola Miyel is the place where the spirit Noyintj lives, this is the spirit of the dead...When any Noongar person dies down in Koreng country, their spirit always comes back to Boola Miyel before it passes onto the great beyond."[8]

Elders Williams and Dean also associate Bluff Knoll with the story of a young woman who set two suitors against each other, resulting in their deaths. The young woman was banished and became a lonely spirit who wails and wanders among the peaks.[8]

Geology[edit]

The path from Bluff Knoll summit.

The mountain as well as the rest of the Stirling Range were formed as Australia broke away from Antarctica. When both the continents began to separate a rift gradually opened. In the first stage of rifting, it began to open in the west, then later the eastern section began to open. The two continents pivoted slightly at a point in the west, which squeezed the sediments at the western end of the break against the Yilgarn block, which forced the sediments up to form the range. The sedimentary rocks that were folded up are 1.2 billion years old. The rocks on the range are mostly sedimentary such as sandstone, quartzite, slate and shale.[7]

Climate[edit]

While there are no weather stations on Bluff Knoll, the Australian Bureau of Meteorology's gridded climate dataset extrapolates the highest average elevation, coldest 0.025° × 0.025° area of the Stirling Ranges (the 6.5 square kilometres (2.5 sq mi) from 34.35° to 34.375° S and 118.25° to 118.275° E;[note 1] just excluding the summit but at a higher average elevation than its pixel) as having, averaged over its extent, a temperate or warm-summer mediterranean climate (Csb) according to the Köppen and Bureau of Meteorology classification systems.[9][10] Alternatively, according to the Trewartha climate classification, it has a temperate oceanic climate (Do) due to insufficiently seasonal precipitation, bordering on Trewartha's humid subtropical climate (Cf) due to its eighth-warmest month (May) being only 0.5 °C (0.9 °F) cooler than 10 °C (50 °F) on average.[11] Due to global warming since the 1961–1990 normals used in the temperature extrapolation, the area may now fall within that zone, but unlikely the summit itself.

Bluff Knoll is the coldest place in Western Australia. Summers are mild while winters are cold by Australian standards; area-wide winter means are comparable to those of Canberra,[12][13] and average August lows at the summit likely brush freezing, with maxima frequently beating the 5.6 °C (42.1 °F) state record low figure set on 16 July 1946 at Salmon Gums and 5 August 1951 at Mount Barker.[14] Diurnal temperature variation is significantly greater in summer than in winter, averaging 12.1 °C (21.8 °F) in January yet only 5.3 °C (9.5 °F) in July. Like most areas of southwestern Australia, more precipitation is recorded in winter, though precipitation events tend to be heavier in summer.

Bluff Knoll is one of only a few places to experience regular snowfalls in Western Australia, with some snow reported in most years. Snow on 20 April 1970 was recorded in Bureau of Meteorology (BOM) records.[15] A heavy snowfall was recorded on 6 October 1992 when 20 centimetres of snow fell and light snow was seen at the base, at 450 metres (1,480 ft).[16] Snow fell on three occasions in 2016 after only falling once in 2015.[17] A flurry was recorded on the peak after 2:00 pm on 19 April 2019—it was the earliest recorded snow event in a calendar year in the history of Western Australia.[18]

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Average high °C (°F) 22.3
(72.1)
21.7
(71.1)
19.7
(67.5)
16.2
(61.2)
12.7
(54.9)
10.1
(50.2)
9.2
(48.6)
9.7
(49.5)
11.9
(53.4)
14.5
(58.1)
17.2
(63.0)
20.6
(69.1)
15.5
(59.9)
Daily mean °C (°F) 16.2
(61.2)
16.2
(61.2)
14.8
(58.6)
12.3
(54.1)
9.5
(49.1)
7.4
(45.3)
6.6
(43.9)
6.7
(44.1)
8.1
(46.6)
10.0
(50.0)
12.2
(54.0)
14.6
(58.3)
11.2
(52.2)
Average low °C (°F) 10.2
(50.4)
10.7
(51.3)
9.9
(49.8)
8.3
(46.9)
6.3
(43.3)
4.7
(40.5)
3.9
(39.0)
3.6
(38.5)
4.4
(39.9)
5.5
(41.9)
7.1
(44.8)
8.7
(47.7)
6.9
(44.5)
Average rainfall mm (inches) 24.1
(0.95)
19.6
(0.77)
32.2
(1.27)
38.4
(1.51)
60.1
(2.37)
62.7
(2.47)
69.4
(2.73)
65.3
(2.57)
58.0
(2.28)
41.6
(1.64)
39.0
(1.54)
25.9
(1.02)
536.3
(21.12)
Average rainy days (≥ 1 mm) 2 3 4 6 9 11 12 11 10 8 6 3 85
Average afternoon relative humidity (%) (at 15:00) 40 42 45 51 60 67 67 64 59 51 46 42 53
Mean daily sunshine hours 8.0 7.0 6.0 5.0 4.0 4.0 4.0 5.0 5.0 6.0 6.0 8.0 5.7
Average ultraviolet index 12.2 11.2 8.5 5.5 3.3 2.5 2.7 3.8 5.8 8.1 10.2 11.8 7.1
Source: Bureau of Meteorology[19][20]

References[edit]

  1. ^ The resolution of the BoM's gridded climate data depends on the variable; temperature is sampled at 0.025°, rainfall at 0.05° (nearest pixel 34.325–34.375° S, 118.225–118.275° E) in the freely-downloadable data, rain days and relative humidity at 0.1° (nearest pixel 34.35–34.45° S, 118.25–118.35° E), sunshine hours at 0.25° (nearest pixel 34.145–34.375° S, 118.125–118.375° E), and UV index at 1.5° (nearest pixel 33.42–34.92° S, 117.75–119.25° E).
  1. ^ a b c "Bluff Knoll". Gazetteer of Australia online. Geoscience Australia, Australian Government. Archived from the original on 10 October 2012. Retrieved 9 September 2020.
  2. ^ a b Laurie, Victoria (2015). The Southwest: Australia's Biodiversity Hotspot. Crawley, Western Australia: UWA Publishing. p. 101. ISBN 9781742585000.
  3. ^ a b "Bluff Knoll". Trails WA. Retrieved 31 October 2021.
  4. ^ "Bluff Knoll hike trail to reopen after bushfire". ABC News. 17 April 2020. Retrieved 31 October 2021.
  5. ^ ABC Great Southern (4 July 2019). "Snow has been falling in Western Australia since records began". ABC News.
  6. ^ a b "Western Australian names". Sunday Times (Perth). No. 1568. Western Australia. 12 February 1928. p. 24. Retrieved 17 April 2017 – via National Library of Australia.
  7. ^ a b M.H.Monroe. "Stirling Range Koi Kyeunu-ruff, Western Australia". Australian through time. Retrieved 17 April 2017.
  8. ^ a b Williams, Jack; Dean, Averil (2007). Boola Miyel: The place of many faces. Batchelor, NT: Batchelor Press. ISBN 9781741311082.
  9. ^ Beck, Hylke E.; Zimmermann, Niklaus E.; McVicar, Tim R.; Vergopolan, Noemi; Berg, Alexis; Wood, Eric F. (30 October 2018). "Present and future Köppen-Geiger climate classification maps at 1-km resolution". Scientific Data. 5: 180214. Bibcode:2018NatSD...580214B. doi:10.1038/sdata.2018.214. ISSN 2052-4463. PMC 6207062. PMID 30375988.
  10. ^ Stern, Harvey; Hoedt, Graham; Ernst, Jeneanne (June 2000). "Objective classification of Australian climates". Australian Meteorological Magazine. 49 (2): 87–96. Retrieved 28 June 2022.
  11. ^ Belda, M; Holtanová, E; Halenka, T; Kalvová, J (4 February 2014). "Climate classification revisited: from Köppen to Trewartha" (PDF). Climate Research. 59 (1): 1–13. doi:10.3354/cr01204.
  12. ^ "CANBERRA AIRPORT COMPARISON". Climate statistics for Australian locations. Bureau of Meteorology. 23 June 2022. Retrieved 28 June 2022.
  13. ^ "CANBERRA AIRPORT". Climate statistics for Australian locations. Bureau of Meteorology. 23 June 2022. Retrieved 28 June 2022.
  14. ^ "Official records (Lowest daily maximum temperatures) for Western Australia". Daily Extremes. Bureau of Meteorology. 28 June 2022. Retrieved 28 June 2022.
  15. ^ "Winter arrives early in WA as cold Antarctic burst delivers April snow for first time since 1970". www.abc.net.au. 19 April 2019. Retrieved 7 December 2020.
  16. ^ "Snowfall dusts WA's Stirling Ranges". PerthNow. 10 August 2015. Retrieved 7 December 2020.
  17. ^ Andrew Collins (9 August 2016). "Snow falls on Bluff Knoll as hikers brave freezing temperatures". Australian Broadcasting Corporation. Retrieved 17 April 2017.
  18. ^ Kaur, Herlyn. "Snow falls in WA in April for first time in 49 years as Good Friday cold blast turns Bluff Knoll white". Weatherzone. Weatherzone. Archived from the original on 20 April 2019. Retrieved 28 June 2022.
  19. ^ "Maps of average conditions". Bureau of Meteorology. Retrieved 27 June 2022.
  20. ^ "Climatological gridded data information - Australian Maps". Gridded climate data. Bureau of Meteorology. Retrieved 28 June 2022.