What is Glacial Lake Outburst Flood?

February 9, 2021

Recently, a massive glacier burst occurred at Chamoli in Uttarakhand. The exact reason for the burst is not yet known. But the incident has brought the focus again to the dangers of climate change. This incident is also being seen as the Glacial Lake Outburst flood.

Glacial Lake Outburst Flood

A type of the outburst flood which occurs when the dam comprising a glacial lake gets fail.
The failure of the dam can happen because of water pressure, erosion, earthquake, avalanche in rock or heavy snow or volcanic eruptions under the ice.
It can also occur because of the huge displacement of water in a glacial lake because of collapse of any glacier into it.
Other reasons for the glacial burst include the construction activities, anthropological activities and climate change.

Subglacial Lake

It is a lake found under a glacier. It is usually formed beneath an ice cap or ice sheet. It is formed at the boundary between ice and the underlying bedrock. At this boundary, the gravitational pressure decreases the pressure melting point of ice.

Proglacial Lakes

The Proglacial lakes are the lakes formed at the tips of the glacial as a result of the retreating glaciers. They are often bound by sediments and boulders In the Himalayas, majority of the glaciers are known to be receding. So, there are several proglacial lakes in the regions.

Concerns

Breach in the boundaries of the proglacial lakes can lead to large amounts of water to rush down to nearby streams and rivers. The water gains the momentum on its way by coming in contact with the sediments, rocks and other materials. This causes flooding downstream.