How deep can crevasses be?

148 feet
Crevasses range up to 20 m (65 feet) wide, 45 m (148 feet) deep, and several hundred metres long. Most are named according to their positions with respect to the long axis of the glacier.

What conditions are necessary to create crevasses within glaciers?

When a glacier moves rapidly around a rock outcrop, flows over a steep area in the bedrock, or accelerates, or over a steep area in the bedrock, internal stresses build up in the ice. These stresses can cause cracks, or crevasses, on the glacier surface.

Do crevasses extend to the bottom of the glacier?

Crevasses are a significant hazard on any glacierised terrain, and can extend all the way down to the bottom of the glacier. They also trap surface water, and can divert surface streams to the base of the glacier. Surface streams aren’t, however, too much of a problem around Rothera at the moment!

What’s the deepest crevasse in the world?

The deepest point on continental Earth has been identified in East Antarctica, under Denman Glacier. This ice-filled canyon reaches 3.5km (11,500ft) below sea level. Only in the ocean are the valleys deeper still.

How are crevasses formed in glaciers?

A crevasse is a crack in the surface of a glacier caused by extensive stress within the ice. For example, extensive stress can be caused by stretching if the glacier is speeding up as it flows down the valley. Crevasses can also be caused by the ice flowing over bumps or steps in the bedrock.

Why don t crevasses penetrate all the way through a glacier?

A crevasse may be covered, but not necessarily filled, by a snow bridge made of the previous years’ accumulation and snow drifts. The result is that crevasses are rendered invisible, and thus potentially lethal to anyone attempting to navigate their way across a glacier.

Why do crevasses form in the top of a glacier?

Crevasses form because the glacier is flowing over a rough uneven surface. Frozen water, as you know, does not easily pour. Thus as the thick sheet of ice moves down the mountain cracks open up in the brittle ice sheet.

How deep are the crevasses in Antarctica?

Sub-surface crevasses can be identified from satellite at depths of up to 10 m. Crevasse visibility is greatest in dry snow areas without summer melting.

How do crevasses form of valley glaciers?

Crevasses also form when different parts of a glacier move at different speeds. When traveling down a valley, for example, a glacier moves faster in the middle. The sides of a glacier are slowed down as they scrape against valley walls. As the sections advance at different speeds, crevasses open in the ice.