glacier

Mass of ice resulting from the accumulation and compression of snow; it moves under its own weight.

terminal moraine

Frontal moraine marking the glacier’s most advanced position before it recedes.

rock basin

Basin dug out of soft rock by a glacier.

glacier tongue

River of ice formed by the flow of the firn.

riegel

A rocky ridge set crosswise to the glacier tongue.

crevasse

Deep narrow fissure that forms on the surface of the glacier.

ground moraine

Deposit of rock debris (till) that is dragged along and deposited under the advancing glacier.

end moraine

Deposit of rock debris scraped from the ground and pushed to the front of the glacier.

outwash plain

Relatively even, gently sloping tract of land, formed by the action of a glacier’s meltwater.

meltwater

Water that runs beneath the glacier tongue, forming rivers and occasionally lakes at the foot of a glacier.

lateral moraine

Deposit of rock debris scraped from the sides of raised land by ice.

serac

Chaotic mass of unstable ice bordered by crevasses.

hanging glacier

Glacier with no tongue that remains in its cirque.

medial moraine

Forms where the lateral moraines of two parallel glacier tongues come together.

glacial cirque

Semicircular cavity with steep sides, carved out by ice.

firn

Accumulation of snow inside a cirque; compressed by its own weight, it is converted into ice and feeds the glacier.

bergschrund

Crevasse between the firn and the rock face; it appears when the glacier breaks away from the rock face.