Bergschrund

{{short description|Crevasse between moving glacier ice and the stagnant ice or firn above}}

File:Glacial Cirque Formation EN.svg showing the bergschrund]]

File:Hintere Schwaerze Nordwand HQ.jpg]]

File:Bergschrunds am Mont Dolent.JPG]]

A bergschrund (from the German for mountain cleft; sometimes abbreviated in English to "schrund") is a crevasse that forms where moving glacier ice separates from the stagnant ice or firn above.Whittow, John (1984). Dictionary of Physical Geography. London: Penguin, 1984, p. 61. {{ISBN|0-14-051094-X}}. It is often a serious obstacle for mountaineers. Bergschrunds extend to the bedrock, and can have a depth of well over {{convert|100|m}}.

A bergschrund is distinct from a randkluft, which is a crevasse with one side formed by rock. The randkluft arises in part from the melting of the ice due to the presence of the warmer rock face.Benn, D.I. & Evans, D.J.A. Glaciers and Glaciation (1998) {{ISBN|0-340-58431-9}} However, a randkluft is sometimes called a bergschrund.Burchfield, R.W. ed. Oxford English Dictionary supplement (1987) {{ISBN|0-19-861211-7}} The French word rimaye encompasses both randklufts and bergschrunds. In a corrie or cirque, the bergschrund is positioned at the rear, parallel to the back wall of the corrie. It is caused by the rotational movement of the glacier. In a longitudinal glacier, the bergschrund is at the top end of the glacier at a right angle to the flow of the glacier. It is caused by the downwards flow of the glacier.

In winter, a bergschrund is often filled by snow from avalanches from the mountain above it. In later summer, due to melting, it lies open and can present a very difficult obstacle to mountaineers.

On the South Col route to reach the summit of Mount Everest, a deep bergschrund lies at the bottom of the Lhotse face, separating Camp II from Camp III.{{cite web| url= http://www.climb8850.com/Everest_South_Col_Route.html|title=Everest South Col Route | website= climb8850.com |archive-url= https://web.archive.org/web/20121128131437/http://www.climb8850.com/Everest_South_Col_Route.html |archive-date=2012-11-28|url-status=dead |access-date= 2012-12-29}}