Westarctica at 05:47, 9 April 2018

2018-04-09T05:47:50Z

← Older revision		Revision as of 05:47, 9 April 2018
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	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.		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 moisten and lubricate the bed and accelerate ice flow.		The presence of water in a crevasse can significantly increase its penetration. Water-filled crevasses may reach the bottom of glaciers or [[ice sheet]]s 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.

	[[Category:Science]]		[[Category:Science]]

Westarctica: Created page with "Crossing a crevasse, Easton Glacier, North Cascades A '''crevasse''' is a deep crack, or fracture, found in an ice sheet or glacier, as opp..."

2018-04-05T23:34:27Z

Created page with "thumb|Crossing a crevasse, Easton Glacier, North Cascades A '''crevasse''' is a deep crack, or fracture, found in an ice sheet or glacier, as opp..."

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[[File:Crevasse.jpg|thumb|Crossing a crevasse, Easton Glacier, North Cascades]]
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==
Crevasses often have vertical or near-vertical walls, which can then melt and create seracs, arches, and other [[ice]] formations. 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 100 meters, as wide as 20 meters, and up to several hundred meters 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 moisten and lubricate the bed and accelerate ice flow.

[[Category:Science]]

Crevasse - Revision history

Westarctica at 05:47, 9 April 2018

Westarctica: Created page with "Crossing a crevasse, Easton Glacier, North Cascades A '''crevasse''' is a deep crack, or fracture, found in an ice sheet or glacier, as opp..."