Glaciology Glossary

All processes by which ice and snow are lost from a glacier, including melting, sublimation, calving, and wind erosion.

All processes by which snow and ice are added to a glacier, including snowfall, avalanching, wind-deposited snow, and refreezing of meltwater.

A narrow, knife-edge ridge formed between two adjacent cirques or glacial valleys that have been eroded by glaciers on both sides.

The movement of a glacier over its bed, facilitated by meltwater lubrication at the ice-bedrock interface.

The process by which pieces of ice break off from the front of a glacier or ice shelf into a body of water.

A bowl-shaped depression carved into a mountainside by the erosive action of a glacier, often containing a small lake (tarn) after deglaciation.

A deep fissure or crack in glacier ice caused by tensile stresses from differential movement or changes in bed topography.

A streamlined, elongated hill of glacial till formed beneath a moving ice sheet, with its long axis parallel to the direction of ice flow.

The elevation on a glacier where annual accumulation exactly balances annual ablation, separating the accumulation and ablation zones.

A rock or boulder transported by glacial ice and deposited in an area of different bedrock composition, often far from its source.

A long, sinuous ridge of stratified sand and gravel deposited by a subglacial or englacial meltwater stream.

Compacted granular snow that has survived at least one ablation season and is in the process of being transformed into glacier ice.

A long, narrow, deep inlet of the sea formed by glacial erosion of a river valley, typically with steep walls and a U-shaped cross-section.

The ongoing vertical movement of Earth's crust in response to the addition or removal of large ice masses, driven by viscous flow in the mantle.

The constitutive equation describing the relationship between stress and strain rate in polycrystalline ice, with strain rate proportional to stress raised to the power n (approximately 3).

The location where a glacier or ice sheet transitions from resting on bedrock to floating on the ocean as an ice shelf.

A mass of glacial ice covering more than 50,000 square kilometers of land. Currently, only the Antarctic and Greenland ice sheets exist on Earth.

A thick floating platform of ice that forms where a glacier or ice sheet flows onto the ocean surface, remaining attached to the coast.

A catastrophic glacial outburst flood resulting from the sudden drainage of a glacier-dammed or subglacial lake.

An accumulation of unconsolidated glacial debris (till) deposited by a glacier, marking current or former ice margins.

A vertical or near-vertical shaft in a glacier through which surface meltwater drains to the glacier's interior or base.

An exposed rocky peak or ridge that protrudes through an ice sheet or glacier, remaining unglaciated while surrounded by ice.

A broad, flat area of stratified sediment deposited by braided meltwater streams flowing away from a glacier terminus.

A dramatic, periodic increase in glacier flow velocity, often by an order of magnitude, lasting months to years before returning to quiescent flow.

Unsorted, unstratified sediment deposited directly by glacial ice, consisting of a mixture of clay, silt, sand, gravel, and boulders.