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Crevasse is also a traditional term for a levee breach.

A crevasse is a deep crack, or fracture, found in an ice sheet or glacier, as opposed to a crevice that 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. 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 up to several hundred metres long.[citation needed]

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.[citation needed]

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 moisten and lubricate the bed and accelerate ice flow.[citation needed]

Types of crevasses[edit]

  • Longitudinal crevasses form parallel to flow where the glacier width is expanding. They develop in areas of tensile stress, such as where a valley widens or bends. They are typically concave down and form an angle greater than 45° with the margin.[2]
  • Splashing crevasses result from shear stress from the margin of the glacier and longitudinal compressing stress from lateral extension. They extend from the glacier's margin 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.[citation needed]
  • Transverse crevasses are the most common crevasse type. They form in a zone of longitudinal extension where the principal stresses are parallel 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]

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 Crevasses at Wikimedia Commons

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.
89098 videos foundNext > 

50 feet down in a crevasse after fall, Chamonix

On February 17, 2015 I was snowboarding off-piste on Glacier des Rognons in the Grands Montets resort in Chamonix and I fell into a deep crevasse.

24-05-2015 Chute en crevasse a ski et secours sur le glacier du Strahlhorn.

Chute et secours en crevasse le 24/05/2015 en descendant du Strahlhorn. Merci au guide suisse Yvan Duc et deux de ses stagiaires Armand et Oriel pour leur ...

Climber films 20m crevasse fall in Himalayas - BBC News

Subscribe to BBC News www.youtube.com/bbcnews Watch this dramatic video as seriously injured US climber John All struggles to survive after falling 70 feet ...

Drone flies in crevasse

Flyability partnered with the team from Zermatt Mountain Rescue of the Zermatt Glacier in the Swiss Alps to explore crevasses situated at an altitude of 3'500 ...

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 can in the ...

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 ...

Helmet Cam Captures Skier Falling Into Glacial Crevasse

Helmet camera captures footage of Benjamin Spilthooren as he skied down the Strah Strahlhorn mountain in the Pennine Alps and fell into a glacial crevasse.

2 Person Rope Team Crevasse Rescue

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

Everest Million - Crossing an Everest crevasse - heart in mouth!

I'm risking it all to raise £1million for Comic Relief, an awesome charity who people in poverty around the world. Follow me live to the top of the world, and ...

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 ...

89098 videos foundNext > 

18874 news items

Gizmodo

Gizmodo
Wed, 03 Feb 2016 09:26:15 -0800

Here's some really cool footage from Flyability that shows a drone exploring a crevasse into the Zermatt Glacier in the Swiss Alps. Flyability says that the ice caves were previously inaccessible to other drones but they managed to get their UAV down ...

Patch.com

Patch.com
Sat, 06 Feb 2016 08:41:15 -0800

Motorcyclist Crashes in Crevasse, Requires Air Rescue. After emergency personnel reached the injured man, a hoist operation was conducted to extricate the victim and airlift him to a hospital. Lake Elsinore-Wildomar, CA. By Renee Schiavone (Patch Staff ...

Discovery News

Discovery News
Thu, 28 Jan 2016 10:53:16 -0800

“The embedded full HD camera, digital live video transmission and the powerful lighting system allowed the drone to operate in the heart of the mountain glacier,” Flyability's press release said. Check out a video of the crevasse from the drone's ...

Motherboard

Motherboard
Wed, 20 Jan 2016 06:32:25 -0800

Look, I'll be honest: I went into this expecting an epic video of a badass drone tearing around the gorgeous, glistening blue guts of a glacier. It was not quite to be, but the crevasse-exploring drone is still an important application of the whole ...

The Guardian

The Guardian
Mon, 11 Jan 2016 16:33:45 -0800

One of the pilots fell down the crevasse after leaving his aircraft, while the second, unable to help, contacted Davis station and flew back for help. “The pilot involved in the incident has considerable Antarctic experience,” the division said on Tuesday.
 
Business Insider
Tue, 12 Jan 2016 22:56:15 -0800

SYDNEY (Reuters) - A Canadian helicopter pilot has died after falling into a crevasse on a remote ice shelf in Antarctica while refueling a depot, the Australian Antarctic Division said on Wednesday. David Wood, 62, a veteran pilot on the continent ...
 
TV Technology
Tue, 19 Jan 2016 12:21:40 -0800

LAUSANNE, SWITZERLAND—Flyability, a Swiss creator of rescue drones, has captured footage of an ice crevasse descent with its Gimball, billed as “the world's first collision-tolerant flying robot capable of remaining stable after contacts and safe to ...

ZIZ Live

ZIZ Live
Wed, 13 Jan 2016 01:33:45 -0800

(BBC) A Canadian helicopter pilot has died after falling 20m (65ft) into an icy crevasse near Australia's Davis base in Antarctica. David Wood, 62, fell into the crack after getting out of his helicopter during a routine fuel drop on Monday. He was ...
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