Ans: ‘Glacial lake outburst flood’ (GLOF) is generally used to describe a sudden release of a significant amount of water retained in a glacial lake. GLOF refers to the flooding that occurs when the water dammed by a glacier or a moraine (accumulations of dirt, sand, pebbles, and rocks fallen onto the glacier surface) is released suddenly or when a dam containing a glacial lake fails.
The direct causes of glacial lake outburst floods are as following:
- Sudden (and sometimes cyclic) releases of water
- Large downstream river discharges (which increase by an order of magnitude)
- Rapid slope movement into the lake
- Heavy rainfall/snowmelt
- Cascading processes (flood from a lake situated upstream)
- Melting of ice incorporated in the dam/forming the dam
- Blocking of subsurface outflow tunnels
- Degradation of dam
- Rise in temperature due to global warming or climate change
Strategy to tackle glacial burst in the Himalayan region:
- Potentially dangerous lakes can be identified based on field observation.
- Maintaining the records of past events like Kedarnath cloudburst and glacier burst in Chamoli district.
- Analysis of geomorphologic and geotechnical characteristics of the lake/dam and other physical conditions.
- Use of the latest technology like Synthetic-Aperture Radar imagery to automatically detect changes in water bodies.
As per Supreme Court and Ravi Chopra committee, the hydroelectric projects in certain locations could pose a disaster risk to few hilly states. Restricting constructions and development in GLOF/LLOF prone areas and the formation of significant policies is a very efficient means to reduce risks and lives of people.