0 a deep crack near or at the top of a glacier, separating moving ice from ice that is not moving --
It is widely held that a common cause for headwall steepening and extension headward is the crevasses known as bergschrund that occur between the moving ice and the headwall.
In a corrie or cirque, the bergschrund is positioned at the rear, parallel to the back wall of the corrie.
It is often a serious obstacle for mountaineers, who sometimes abbreviate bergschrund to schrund.
In a longitudinal glacier, the bergschrund is at the top end of the glacier at a right angle to the flow of the glacier.
In winter, a bergschrund is often filled by snow from avalanches from the mountain above it.
A bergschrund forms when the movement of the glacier separates the moving ice from the stationary ice forming a crevasse.
It involves crossing a number of crevasses in the glacier and may be impassible due to wall-to-wall bergschrund at the upper end.
Towards the summit was a bergschrund, in most places 30ft m wide, traversing the width of the glacier, and impassable without a long ladder.