Crevasses also form when different parts of a glacier move at different speeds. When traveling down a valley, for example, a glacier moves faster in the middle. The sides of a glacier are slowed down as they scrape against valley walls. ... Sometimes, a thin layer of snow may form over a crevasse, creating a snow bridge.

How are crevasses formed?

A crevasse is a crack in the surface of a glacier caused by extensive stress within the ice. For example, extensive stress can be caused by stretching if the glacier is speeding up as it flows down the valley. Crevasses can also be caused by the ice flowing over bumps or steps in the bedrock.

How does a crevasse form quizlet?

when a valley glacier comes to a steep slope, cracks called crevasses form. They form because the ice near the surface of the glacier is rough and rigid. The ice responds to the movement of the ice underneath it by breaking. ... it is the unsorted and unstratified rock that is deposited by a melting glacier.