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Crossing a crevasse on the Easton Glacier, Mount Baker, in the North Cascades, Washington

A crevasse is a deep crack in an ice sheet or glacier, as opposed to a crevice, which forms in rock. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement. The resulting intensity of the shear stress causes a breakage along the faces.

Description[edit]

Crevasses often have vertical or near-vertical walls, which can then melt and create seracs, arches, and other ice formations.[1] These walls sometimes expose layers that represent the glacier's stratigraphy. They are widely distributed across Antarctica and are more narrow at depth as it is here that pieces of the glacier may rub and break against each other. Crevasse size often depends upon the amount of liquid water present in the glacier. A crevasse may be as deep as 45 metres, as wide as 20 metres, and can be up to several hundred metres long.

A crevasse may be covered, but not necessarily filled, by a snow bridge made of the previous years' accumulation and snow drifts. The result is that crevasses are rendered invisible, and thus potentially lethal to anyone attempting to navigate their way across a glacier. Occasionally a snow bridge over an old crevasse may begin to sag providing some landscape relief, but this cannot be relied upon. Anyone planning to travel on a glacier should be trained in crevasse rescue.

The presence of water in a crevasse can significantly increase its penetration. Water-filled crevasses may reach the bottom of glaciers or ice sheets and provide a direct hydrologic connection between the surface, where significant summer melting occurs, and the bed of the glacier, where additional water may lubricate the bed and accelerate ice flow.

Types of crevasses[edit]

  • Transverse crevasses are the most common crevasse type and they form in a zone of longitudinal extension where the principal stresses are normal to the direction of glacier flow, creating extensional tensile stress. These crevasses stretch across the glacier transverse to the flow direction, or cross-glacier. They generally form where a valley becomes steeper.[2]
  • Splashing crevasses form as a result of shear stress from the margin of the glacier, and longitudinal compressing stress from lateral extension. They extend from the margin of the glacier and are concave up with respect to glacier flow, making an angle less than 45° with the margin. At the centre line of the glacier, there is zero pure shear from the margins, so this area is typically crevasse-free.
  • Longitudinal crevasses form parallel to flow where the glacier width is expanding. They develop in areas of compressing stress, such as where a valley widens or bends. They are typically concave down-glacier, and form an angle greater than 45° with the margin.[2]

Gallery[edit]

Crevasses around the world
Crevasse on the Gorner Glacier, Zermatt, Switzerland 
Measuring snowpack in a crevasse on the Easton Glacier, Mount Baker, North Cascades, United States 
Exploring the bottom of a crevasse in Antarctica 
Crevasse on the Ross Ice Shelf, January 2001 
Crevasses on the Upper Price Glacier of Mt. Shuksan, North Cascades, WA. Photo taken August 2011 
Split-boarder skinning up past open crevasses on the Coleman Glacier of Mt. Baker. Photo taken October 2009 
Looking down into a crevasse on Mt. Rainier, Cascade range, WA. Photo taken Mid August 2009 
Crevasses on Mt. Rainier. Photo taken from the Disappointment Cleaver Route on Mt. Rainier. Photo taken August 2009 
Mountaineers crossing a crevasse on Mt. Rainier. Photo taken August 2009 
Ladder bridging a crevasse on Mt. Rainier. Photo taken Aug. 2009 

See also[edit]

References[edit]

  1. ^ van der Veen, C (1990). "Crevasses on Glaciers". Polar Geography 23 (3): 213–245. 
  2. ^ a b Holdsworth, G (October 1956). "Primary Transverse Crevasses". Journal of Glaciology 8 (52): 107–129. 

Bibliography[edit]

  • Paterson, W.S.B., 1994, The Physics of Glaciers, 3rd edition, ISBN 0-7506-4742-6.
  • Boon, S., M.J. Sharp, 2003, The role of hydrologically-driven ice fracture in drainage system evolution on an Arctic glacier, Geophysical Research Letters, 30, pp. 1916.
  • van der Veen, C.J., 1998, Fracture mechanics approach to penetration of surface crevasses on glaciers, Cold Regions Science and Technology, 27, pp. 31–47.
  • Zwally, H.J., W. Abdalati, T. Herring, K. Larson, J. Saba, K. Steffen, 2002, Surface melt-induced acceleration of Greenland ice-sheet flow, Science, 297, pp. 218–222.
  • Mountaineering: The Freedom of the Hills, 5th edition. ISBN 0-89886-309-0.
  • "Crevasse." Encyclopædia Britannica. 2010. Encyclopædia Britannica Online. 17 Oct. 2010.
  • Das, S. B., I. Joughin, M.D. Behn, I.M. Howat, M.A. King, D. Lizarralde, M.P. Bhatia, 2008, Fracture propagation to the base of the Greenland Ice Sheet during supraglacial lake drainage, Science, 320, pp. 778.

External links[edit]

  • Media related to Crevasse at Wikimedia Commons

Templates[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Crevasse — Please support Wikipedia.
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The Local.ch
Sun, 13 Apr 2014 13:11:37 -0700

A 50-year-old man lost his life on the weekend after falling into a crevasse while crossing a glacier in Fieschertal in the canton of Valais. Mountain guide dies from fall in Alpine crevasse (01 Apr 14); Heli-skiing guide and woman die in avalanche (17 ...
 
GenevaLunch news
Mon, 14 Apr 2014 00:07:30 -0700

GENEVA, SWITZERLAND – A 50-year-old man from canton Solothurn who was ski touring on the Gletscherhornfirn Saturday 12 April died when he fell into a crevasse. He was part of a group of three who were coming down from Gletscherjoch, heading ...
 
The Local.ch
Tue, 01 Apr 2014 01:31:30 -0700

A 48-year-old Swiss mountain guide died on Monday after falling into a crevasse on the Corbassière glacier in the canton of Valais. Avalanche victim dies after night in Alpine igloo (25 Mar 14); Heli-skiing guide and woman die in avalanche (17 Mar 14) ...

KTVB

KTVB
Thu, 27 Mar 2014 06:32:30 -0700

A hornets' nest was opened in Chicago yesterday by the National Labor Relations Board, and you can't run from it. The NLRB ruled in favor of Northwestern football players in their quest for the right to unionize. To try to count the ramifications of ...
 
Victoria News
Wed, 02 Apr 2014 10:15:00 -0700

"It's your only move, Lemon. Sometimes the way back up is down. Let me tell you a story. It's 1994. I went ice climbing, and I fell into a crevasse. I hurt my leg, and I couldn't climb back up. So fighting every natural instinct, doing the thing that ...

Cinema Blend

Cinema Blend
Wed, 16 Apr 2014 17:43:47 -0700

Judging from this image, it would seem that at least one scene in the movie will have the star actually going down into a giant crevasse created by the aforementioned natural disaster. San Andreas - which has nothing to do with the Grand Theft Auto ...
 
Teton Gravity Research (press release) (blog)
Wed, 16 Apr 2014 14:10:02 -0700

After four hours of skinning, including Halvy's first experience with AK's unique glacier travel challenges, including false snow bridges and a bergschrund with a bottomless crevasse, they booted straight up one of the 4,000-foot couloirs, and two ...

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Sun, 13 Apr 2014 07:03:45 -0700

Un Soleurois de 50 ans a perdu la vie samedi vers 13 heures en chutant dans une crevasse au Gletscherhornfirn. Un groupe de trois randonneurs descendait du "Gletscherjoch" en direction de la "Konkordiaplatz". A une altitude de 3450 m, un pont de neige ...
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