How do glaciers move?

A glacier is a huge mass of ice that flows because of gravity and its own enormous weight. Movement happens in two main ways. First, pressure and a thin film of meltwater at the base let the whole glacier slide over the ground, a process called basal sliding. Second, the ice itself deforms internally, with layers slowly shearing past one another under pressure. Most glaciers creep forward only a few centimetres to a metre or so per day, though some surge much faster. As they move, glaciers grind and carve the landscape, forming valleys, ridges, and lakes.