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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.
63110 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...

Extreme Snowboarder falls into Crevasse

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

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.

Skier Falls into Crevasse - Hangs by one toepiece

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

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...

Macross Frontier - Shinkuu no Diamond Crevasse

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Himlung Crevasse Fall 01

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63110 videos foundNext > 

9838 news items

NOLA.com

NOLA.com
Fri, 02 Jan 2015 07:22:30 -0800

CANO hosts a free country brunch at Crevasse 22, a "picturesque exhibit of outdoor sculpture by 10 New Orleans artists arranged beside a placid lake that marks the site of a 1922 flood caused by levee break in Poydras, La." New Orleans gospel singer Jo ...
 
NOLA.com
Wed, 21 Jan 2015 13:19:25 -0800

By far, the outdoor/indoor art installation known as Crevasse 22 claims the most picturesque setting of the Prospect.3 New Orleans art festival events. Located in Poydras, a tiny downriver community in St. Bernard Parish, Crevasse 22 -- which is open ...

Daily Mail

Daily Mail
Wed, 21 Jan 2015 03:50:16 -0800

An adventurous photographer, Kent Mearig, couldn't resist scaling a 50-foot deep ice crevasse - simply because it lay within the city limits of his hometown. With an ice axe in hand, the 33-year-old local resident drove, kayaked and trekked the 10 ...

Co.Design

Co.Design
Wed, 28 Jan 2015 10:08:38 -0800

That's anecdotal, but just look at the use cases—we shove our smartphones into every dark crevasse of our clothing and bags, then rip them out one-handed 150 times a day to be checked. An iPhone has the usage burden of a piece of factory equipment.
 
LubbockOnline.com
Wed, 28 Jan 2015 15:12:54 -0800

According to an article by H. Allen Anderson in the Handbook of Texas, Wade was named chief scientist for Byrd's 1939-40 expedition. He suffered severe frostbite and nearly fell into a crevasse. For some of the expeditions, the explorers used a kind of ...

Telegraph.co.uk

Telegraph.co.uk
Wed, 28 Jan 2015 02:10:30 -0800

Until that's the moment you hit an unseen bump and go careering off into a tree, skier, or crevasse. The goggles can project slalom-style gates in front of the wearer. Some of the goggles' elements are genuinely mind-blowing and have the potential to ...

Carluke Gazette

Carluke Gazette
Wed, 28 Jan 2015 07:00:00 -0800

After a gruelling 570- mile/41 day trip in which snow collapsed beneath his skis at one point to reveal a gaping crevasse, heroic Newall Hunter eventually arrived at the South Pole on January 4. His daily website log explained his narrow escape from ...
 
Insurance News Net
Tue, 27 Jan 2015 08:18:31 -0800

As a result, an increasing number of systems have made the decision to "cross the crevasse" and secure their own insurance licenses. Futurist Ian Morrison has described this type of dynamic as moving to the second business curve, where disruptive ...
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