Moulin (geomorphology)

[1][2] They can be up to 10 meters wide and are typically found on ice sheets and flat areas of a glacier in a region of transverse crevasses.

Moulins are parts of the internal structure of glaciers, that carry meltwater from the surface down to wherever it may go.

[7] Water from a moulin often exits the glacier at base level, sometimes into the sea, and occasionally the lower end of a moulin may be exposed in the face of a glacier or at the edge of a stagnant block of ice.

Water from moulins may help lubricate the base of the glacier, affecting glacial motion.

Given an appropriate relationship between an ice sheet and the terrain, the head of water in a moulin can provide the power and medium with which a tunnel valley may be formed.

A hiker peers into a large moulin on Snowbird Glacier , in the Talkeetna Mountains of Alaska
Schematic drawing of glacial features illustrating how moulins transport surface water to the base of the glacier
Surface water entering a moulin on Athabasca Glacier