Glacier

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Glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years. Columbia Icefields, Alberta Canada
Glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years. Columbia Icefields, Alberta Canada
Columbia Icefields, Alberta Canada
Columbia Icefields, Alberta Canada
Cross section of an alpine glacier showing snow being converted into glacier ice (the left side of the figure) and the two major zones of a glacier’s surface. The red arrows show the direction and relative speed of different parts of the glacier. The longer the arrow, the faster ice is moving.
Cross section of an alpine glacier showing snow being converted into glacier ice (the left side of the figure) and the two major zones of a glacier’s surface. The red arrows show the direction and relative speed of different parts of the glacier. The longer the arrow, the faster ice is moving.

Glacier is a perennial mass of ice which moves over land. A glacier forms in locations where the mass accumulation of snow and ice exceeds ablation over many years.

The word glacier comes from French via the Vulgar Latin glacia, and ultimately from Latin glacies meaning ice. The corresponding area of study is called glaciology.

Glacier ice is the largest reservoir of fresh water on Earth, and is second only to oceans as the largest reservoir of total water. Glaciers cover vast areas of the polar regions and are found in mountain ranges of every continent including Australasia (there are glaciers in New Zealand).

In the tropics glaciers are restricted to the highest mountains. The processes and landforms caused by glaciers and related to them are referred to as glacial. The process of glacier growth and establishment is called glaciation.

Glaciers are indicators of climate and are important to world water resources and sea level variation. They are an important component of the more encompassing cryosphere.

As new snow accumulates, it buries and compresses the old snow. Under the weight of the overlying snow, the old snow is transformed from a fluffy mass of ice crystals into dense, hard ice.

This process occurs on the upper part of a glacier, at higher altitudes, where more snow accumulates than is lost each year. This is called the “accumulation zone”, and is typically covered with snow year-round.

The glacier is in constant motion, and the ice in the accumulation zone flows down to lower altitudes, which is called the “ablation zone”. The ablation zone is located in the lower part of the the glacier where more snow is lost than accumulates. In late summer, when the seasonal snow has melted, the bare ice of the ablation zone is exposed.


Glaciers and ice caps

Glaciers and ice caps (lowest and [highest] estimates):

  • Area Covered (million square km)0.51 [0.54]
  • Ice Volume (million cubic km)0.05 [0.13]
  • Potential Sea Level Rise (cm)15 [37]

Source: IPCC 2007

Also See

Reference:

  • Wikipedia see Glacier [1]
  • Rocky Mountain National Park Glacier Basics [2]
  • Glaciers and Ice Caps [3]

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