GLOF: Glacial Lake Outburst Flood

Hello Everyone,

This post is an emotional but informational post which i wanted to share with all the readers. On Sunday we witnessed a massive breach in the one of the dams in Nanda Devi Glacier which was placed in Chamoli's District of Uttarakhand, a northern state in India crossed by Himalayas. The glacier break caused a huge devastation in the upper reaches of the ecologically fragile Himalayas. Over 150 laborers working at the bottom of the hill in a power project are still missing out of which 10 bodies has been recovered so far.

What is a Glacier? and how are they formed?

Glaciers are made up of snow that, over many years, compresses into large, thick ice masses. Glaciers form when snow remains in one location long enough to transform into ice. What makes glaciers unique is their ability to flow. Due to sheer mass, glaciers flow like very slow rivers. Some glaciers are as small as football fields, while others grow to be dozens or even hundreds of kilometres long.

According to National Snow and Ice Data Center, "Ice may flow down mountain valleys, fan out across plains, or in some locations, to form glaciers"

“Glacial lake outburst flood” (GLOF) is a phrase used to describe a sudden release of a significant amount of water retained in a glacial lake, due to a dam failure.

Causes of GLOF

1. Rapid slope movement into the lake
2. Heavy rainfall/snow melt
3. Cascading processes (flood from a lake situated upstream)
4. Earthquake
5. Melting of ice incorporated in dam/forming the dam (including volcanic activity)
6. Blocking of subsurface outflow tunnels
7. Long-term dam degradation

Prediction of GLOF

In the past deadly and destructive glacial floods have occurred in Peru and Nepal.

A number of imminent deadly glacier burst and flood situations have been identified worldwide, including in the Himalayas and South American Andes.

But the remote locations of glaciers and a lack of monitoring mean we do not have a clear understanding of how often they occur and if they are increasing. Given the overall pattern of global warming, glacier retreat, and increase in infrastructure projects, seems natural that these events will occur more frequently and will become overall more destructive if measures are not taken to mitigate these risks.

Preventive Measures

1. Making a tunnel through the moraine dam
2. Pumping water out of the lake
3. Construction of an outlet structure
4. Controlled Breaching

**image source - https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT6WZ1FSESPhmaQNZb18i8yzM82LAFMBspjLw&usqp=CAU

Posted with STEMGeeks