A glacier is a thick mass of ice, which moves over the ground under the influence of gravity. It originates on land from compaction and recrystallization of snow. Glaciers form in places in places where more snow accumulates each year than that melts away. They are found chiefly in high latitudes as in Arctic regions or in high altitudes as on high mountains like Andes, Rockies, Eurapean Alps, Alaska’s Brooke Range, and Himalayan mountains above the snow line. The snow line is the lower limit of accumulating snow. Below the snowline the snow melts in summer. The elevation of the snowline varies considerably. In polar regions it may be at sea level, whereas in areas near the equator, the snowline may occur at 6000 meters. In the Himalayas the snowline lies at altitudes varying between 4200 to 5700 meters.

Types of Glaciers

There are three kinds of glaciers; (i) valley glaciers, (ii) piedmont glaciers, and (iii) ice sheets.

(i). Valley Glaciers: The glaciers, which originate near the crests of high mountains and move along the valleys just like rivers, are called valley glaciers”.

(ii). Piedmont Glaciers: At the end of a hilly region, a number of valley glaciers may unite to form a comparatively thick sheet of ice. Such a compound glacier is called the “Piedmont Glacier”.

(iii). Ice Sheets: These are massive accumulations of ice covering extensive areas. Two such glaciers that exist today are the Greenland and Arctic Ice Sheets. The Greenland ice sheet covers an area of about 1.7 million square kilometers and is over 1500  meter thick.

Process of Glaciation