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Crevasse is also a traditional term for a levee breach.

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 skiing 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. doi:10.1080/10889379909377677. 
  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.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
73523 videos foundNext > 

Inside a crevasse on Mt. Rainier's Nisqually Glacier

My BCC (Basic Climbing Class) team lowers me into a small crevasse on the Nisqually Glacier on Mt. Rainier to practice the "z-pully", a method of crevasse re...

mike falls in crevasse

glacier riding at artic man and snow bridge falls in behind me as mike was following, you can hear his sled go in as I crest over the hill, listen for the ca...

Climber films 20m crevasse fall in Himalayas - BBC News

Watch this dramatic video as seriously injured US climber John All struggles to survive after falling 70 feet (20m) into a crevasse in the Himalayas. He brok...

Programa "I Shouldn't Be Alive" (Sobreviví), Episodio "Killer Crevasse" (Discovery Channel)

Video publicado con el objetivo de difundir nuestro trabajo y asesorías en Coordinación de Stunts y Coreografía de Peleas. Video posted for the purpose of sh...

Crevasse Rescue

A practical demonstration of crevasse rescue using an unassisted hoist. Taken from the Mountaineering Council of Scotland's Alpine Essentials DVD. Full DVD a...

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This video shows my variation for 1 on 1 Crevasse Rescue. Presenter - Darrell Weston Fallen Climber - Dana Tofell Videographer - Matt Blecharz.

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After a morning of powder Brad managed to find a small Crevasse in the mountains of Japan.

Dramatic Video: Injured climber films his own escape from a Himalayan crevasse

Subscribe to ITN News: http://bit.ly/1bmWO8h An American climber escaped alive after falling into a 22-metre crevasse on a Himalayan mountain in Nepal. John ...

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25860 news items

Clapway

Clapway
Wed, 12 Nov 2014 13:32:19 -0800

Let's just put the obvious out there: The North Face Crevasse Backpack ($99.00) isn't for extreme, nine-month-long adventures. No—it was made for slower paced, compact day activities like gallivanting through Rome, or even a leisure hike on the ...
 
NBCSports.com
Tue, 25 Nov 2014 06:26:15 -0800

If Judge Jones scuttles the suspension with a written decision that sharply criticizes the NFL's handling of the Rice investigation, the entire issue could largely disappear into the four-day crevasse of cranberry stuffing. Sure, it would be mentioned ...

NDTV

People Magazine
Fri, 23 May 2014 08:58:44 -0700

A Western Kentucky University professor is recovering from serious injuries after hiking on a research trip and surviving a harrowing, 70-foot fall into an ice crevasse in Nepal. John All, 44, used an ice axe and one arm to fight his way back to the ...
 
Telegraph.co.uk
Mon, 24 Nov 2014 23:52:30 -0800

The early shots of Jones, 34, pulling off big air tricks were shot on the Mont Fort glacier high above Verbier, but some sequences were filmed in Zermatt after a crevasse opened up in the approach to one of the man-made kickers built from scratch ...

International Business Times

TIME
Sat, 24 May 2014 10:07:17 -0700

Professor John All fell 70 feet into an icy crevasse as he was hiking a Himalayan mountain. He had a broken arm, broken ribs, and was all by himself. It's a story that feels like the premise to the survival drama 127 Hours – and indeed, All recorded ...

Francetv info

Francetv info
Sat, 08 Nov 2014 08:04:44 -0800

Ce matin, un snowboardeur italien et sa copine skiaient dans une zone hors-piste sur le glacier de la Grande Motte, quand l'homme a fait une chute d'une dizaine de mètres dans une crevasse. Sa copine a alerté d'autres skieurs. Les secours sont ...

Popular Science

Popular Science
Mon, 24 Nov 2014 11:52:30 -0800

When complete, glacier enthusiasts will be able to see the deep blue ice characteristic of glaciers and view the inside of a crevasse without falling into one. There are other, natural ice caves in Icelandic glaciers, but those are seasonal -- forming ...

BBC News

BBC News
Mon, 20 Oct 2014 10:42:11 -0700

A young Belfast man is giving up his job in Northern Ireland to work in a French ski resort, even though he was almost killed there earlier this year. Matt Allum fell at high speed into a 60ft crevasse in the French Alps, near Chamonix. The incident ...
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