Glacier is a large mass of moving ice. We see glaciers in various mountain ranges and vallies of the world. In the Alps alone there are as many as 1,200 glaciers. In the high mountains of the Alaska, there are around thousands of glaciers with length, ranging from 30 to 60 kilometres.

            The process for the formation of glaciers is described below. During snowfall snow slides down on the slopes of mountains. After a considerable time it accumulates in big quantities. As this accumulated snow does not melt even in summers, its quantity keeps on increasing. As the quantity of snow increases, the pressure on the lowest layer of the snow also increases. Due to the increased pressure and other atmospheric effects, air leaks out from the lowest layer of snow and consequently, it becomes hardened. This process goes on till a time comes when glaciers become heavy enough to flow downhill under their own weight.

            Glaciers are mainly of two kinds. The first type is the valley glaciers. When there is snowfall on the mountains, the snow slides down on the slopes. This gets deposited in the spaces between the mountains. When snow accumulates in big quantities, it often starts sliding down. The slow moving river of ice is called the valley glacier. Large chunks of stones coming in the way of this river move forward with this river and break into pieces due to friction and collisions with other stones. They spread uniformly in all directions. The motion of the glacier thus forms valleys.

 

           The second type of glaciers is continental glaciers. There are many such glaciers in Greenland. In plains, when the accumulated snow crosses a certain limit, it starts sliding. Such sliding mountains of ice are called the continental glaciers. When these glaciers reach the sea, they break into large chunks of ice and thus icebergs are formed.

          Glaciers are found in all the countries of the world. The Zambert glacier of South Australia is the largest glacier of the world. This is 400 km long and 64 km broad. In addition, Zermatt in Switzerland, Lom in Norway, Bosson in France and Nisqually in America are the main glaciers of the world.