A glacier is any large mass of snow or ice that persists on land for many years. Glaciers form in areas where more snow falls than melts. As this snow accumulates it compresses into thick, dense, solid ice. Glaciers actually move because their own weights causes a type of melting to occur, allowing movement —downhill if on a slope or in all directions from the center if on a flat surface.
North Polar ice cap:
South Polar ice cap:
Iceberg:
Iceberg video:
A video that contains an overview of the cryosphere and the movement/ seasonal retreats of glaciers
