Glacier

What is a glacier?

Simply put, a glacier is an old river of ice. Some are small, river-like alpine glaciers that are found high up in mountains, while other are massive flows of inland ice such as those seen on Antarctica and in Greenland.

How is a glacier formed?

A glacier is formed when lots of snow falls in the same place.  Over time, several layers of snow fall on the old snow. The layers get so heavy that the snow at the bottom is compressed.

The lower layers start to flow because the pressure from the upper layers twists, presses and melts them. This makes the whole glacier move slowly like an extremely thick liquid.

 This makes the whole glacier move slowly like an extremely thick liquid.

Do all glaciers flow down slopes?

Glaciers can flow without a slope. They can be compared to a blancmange.  If you put more on top of a blancmange, the weight will make the rest spread out to the sides.  Glaciers are just far

thicker than a blancmange so they move extremely slowly.

The glaciers on the coast of Greenland, Chile, Alaska and Antarctica have a violent end. It is said that they ‘calve’. On their way to the sea they are pushed over uneven ground. This can create

cracks and fissures. When the glaciers reach the sea, the ice breaks off at these cracks.

If the glacier ice flow is still intact when it meets the sea, it does not break off straight away. The waves bore it out from below. Over time, the higher layers are no longer supported and fall into the sea.

This is how icebergs are formed.

On Antarctica and in Greenland, these icebergs can be as tall as skyscrapers if they were measured from top to bottom.