USGS Classification of a Glacier

Calving Glacier

• A calving glacier ends at a body of water, such as a lake or an ocean. Accordingly, pieces of the glacier sometimes break off into the water and form icebergs (a process known as "calving," from which these glaciers derive their name).

Cirque Glacier

• The term cirque refers to a type of mountain basin, a sort of natural amphitheater formed by three steep sides and a fourth open side leading to a valley or similar geological structure. A cirque glacier is a glacier that appears in a cirque basin.

Hanging Glacier

• A hanging glacier runs along the wall of a glacier valley, but only descends part way down that wall. Chunks of ice and snow often break off from it and fall to floor of the valley beneath it, creating avalanches.

Piedmont Glacier

• A Piedmont glacier begins in a narrow geographical feature, such as a valley, which then opens up onto a wider plain. The glacier follows the geographical features of the surroundings: starting out narrow and then expanding when it reaches the plain.

Polar Glacier

• A polar glacier exists anywhere that the temperature of the ice never rises above freezing, such as in the Antarctic or certain northern locales.

Reconstituted Glacier

• A reconstituted glacier appears when the snow and ice that fall off of a hanging glacier grow high enough to connect up with the hanging glacier. Melting ice created by the pressure connect the two halves of the glacier together again to create a single sheet of ice.

Temperate Glacier

• A temperate glacier appears in (comparatively) warm climates. Part of the glacier may melt, creating a mixture of water and glacier ice on its surface during part of the year.

Tidewater Glacier

• A tidewater glacier is similar to a calving glacier in that it terminates in a body of water. In this case, the water experiences a tidal cycle: an ocean or the like. Tidewater glaciers often produce icebergs, but not always.

Valley Glacier

• A valley glacier appears almost entirely within a valley, making it comparatively narrow.

Rock Glacier

• A rock glacier isn't strictly a glacier; instead, it's a rock formation that resembles a glacier; it's created by large chunks of rocks pressed together along a valley or similar geological feature.