Glaciers Unveiled

A glacier is a huge mass of ice that forms near the Earth's poles or on mountains.

Accumulation refers to the addition of snow and ice to a glacier, while ablation refers to the wastage or loss of ice from a glacier.

Glacier mass balance refers to the difference between the amount of snow and ice accumulation and ablation on a glacier.

Sublimation is the process of directly converting ice into water vapor, while calving is the process of ice breaking off from a glacier and forming icebergs.

A glacier's terminus is the end or lower part of a glacier where it meets the surrounding land or water.

If all the world's glaciers melted at once, sea level would rise about 215 feet.

Glaciers form in areas where snow falls more often than it melts. The layers of snow build up and compress under the increasing weight, eventually turning into glacier ice.

Accumulation refers to the addition of snow and ice to a glacier.

Snowfall directly onto the glacier, freezing rain, wind-blown snow, and snow flowing onto the glacier via an avalanche.

Ablation refers to the removal of snow or ice from a glacier.

Melting, wind erosion, and calving (when large chunks of ice break off the glacier and fall into the water).

Sublimation is the direct change from a solid to a gas.

The terminus is the leading edge or snout of the glacier.

Scientists measure the location of the terminus. If the terminus does not travel as far as it previously did, the glacier is retreating. If the terminus moves forward faster than the rate of ablation, the glacier is advancing.

The glacier mass balance is the balance between accumulation and ablation. If there is equal balance, the glacier is in equilibrium and does not change in size. If there is more growth than melting, the glacier has a positive mass balance and will advance. If there is a loss of mass due to faster wasting than growth, the glacier has a negative mass balance and will retreat.