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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 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. 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.
74563 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...

Extreme Snowboarder falls into Crevasse

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

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)

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Skier Falls into Crevasse - Hangs by one toepiece

Ben Ditto falls into a crevasse in Alaska and is saved by his Dynafit toepiece!

2 Person Rope Team Crevasse Rescue

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Fail Ice crevasse in Nepal video American professor John All records his ordeal after falling down an ice crevasse doing research in Nepal. American professo...

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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74563 videos foundNext > 

12646 news items

 
PisteHors.com
Wed, 25 Feb 2015 15:15:00 -0800

Last week Brandon, an American tourist on his first day of a ski trip to Chamonix, founds himself at the bottom of a crevasse. Boarding on the glacier de Rognon he didn't see the crevasse as it was bridged with fresh snow, there were many tracks across ...
 
bestofneworleans.com
Mon, 02 Feb 2015 14:17:06 -0800

One P.3+ site that was worth the drive — and which remains open through February — is Crevasse 22, a sculpture garden and art show at the site of the 1922 levee break in Poydras. On a nice day, the site is sublime by itself, but with the art and Old ...

Midi Libre

Midi Libre
Fri, 27 Feb 2015 07:00:00 -0800

Roger Maurel, randonneur avignonnais, fait une chute mortelle dans une crevasse Roger Maurel était un féru de randonnées en raquettes. il est décédé jeudi 26 février après avoir chuté dans une crevasse. DR ...

L'Obs

L'Obs
Sat, 28 Feb 2015 07:56:15 -0800

Jeudi après-midi, un couple de randonneurs en raquettes, évoluait sur le glacier de La Girose, à 3.450 mètres d'altitude, à La Grave (Hautes-Alpes), quand le mari, âgé de 61 ans, est tombé dans une crevasse. Une chute d'une vingtaine de mètres. A l ...

Le Parisien

Le Parisien
Thu, 26 Feb 2015 10:54:11 -0800

Un randonneur en raquettes a fait une chute mortelle ce jeudi après-midi dans une crevasse à La Grave (Hautes-Alpes), a annoncé la CRS Briançon. Selon le Dauphiné, l'homme évoluait sur le glacier de la Girose lorsqu'il a chuté dans la crevasse.

WCPO

WCPO
Sun, 01 Mar 2015 03:37:30 -0800

After falling into a four-goal crevasse in the first period on Saturday, Miami climbed halfway out before tumbling all the way back to the bottom. The No. 5 RedHawks ended up splitting their series at No. 7 Denver, dropping a 6-2 decision at Magness ...

STLtoday.com

STLtoday.com
Sun, 01 Mar 2015 04:19:25 -0800

Lifts descend nearly 50 feet into a glacier to a palace of fanciful ice sculptures and an ice tunnel leading to a crevasse and icy toboggan run. While Zermatt has grown with its international fame, it remains isolated at the end of a valley where cars ...
 
Le Dauphiné Libéré
Thu, 26 Feb 2015 21:01:36 -0800

Suivez toute l'actualité de votre région en continu sur le support de votre choix. Rester connecté avec les infos, images et vidéos à Grenoble, Annecy, Chambéry, Avignon, Valence, Gap et plus généralement en Isère, Savoie, Haute-Savoie, Ain, Drôme, ...
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