Illustrated Glossary of Alpine Glacial Landforms

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CREVASSE

A crack in the upper 30 meters (100 feet) of a glacier. Ice in approximately the upper 30 meters of glaciers tends to be brittle and as the glacier flows, cracks develop. In general, crevasses rarely extend much deeper than 30 meters because below this depth the ice is too plastic and any surficial cracks close.
The crevasses in the photo to the right are on the Athabaskan Glacier in Alberta, Canada. The people provide an indication of scale. Debris such as rocks, silt, sand and other particles cover the surface of the glacier giving it a gray color. Some of this debris may have fallen on the glacier surface from the surrounding valley walls, and some of the debris is material that was embedded within the glacier and that has been slowly revealed as the ice has melted. Photo: B. Ford. Used with permission.
The photo below shows a close-up view of a small crevasse on the Mendenhall Glacier, Alaska. The crevasses on the Mendenhall Glacier are represented as blue lines on the topographic map.
Photo: L. Freeman. Used with permission.

| Virtual Geography Department Project | Physical Geography Working Group |
All commercial rights reserved. Copyright 2010 by Karen A. Lemke. Earlier copyright 2002 by Karen A. Lemke, and 1998 by Karen A. Lemke and Linda Freeman.
Last updated June 2010 KAL.