Part of: GS Prelims and GS- III – Environment & GS- I – Geography
In news
A glacier break is suspected to have caused the flash floods in Uttarakhand’s Chamoli.
Important value additions
When glaciers melt, the water in glacial lakes accumulates behind loose, natural “glacial/moraine dams” made of ice, sand, pebbles, and ice residue.
A GLOF refers to the flooding that occurs when the water dammed by a glacier or a moraine is released suddenly.
Unlike earthen dams, the weak structure of the moraine dam leads to the abrupt failure of the dam on top of the glacial lake, which holds a large volume of water.
A failure of the dam has the potential of releasing millions of cubic metres of water in a short period, causing catastrophic flooding downstream.
NDMA has recommended the use of Synthetic-Aperture Radar imagery to automatically detect changes in water bodies, including new lake formations, during the monsoon months.
Reasons
Glacial retreat due to climate change occurring in most parts of the Hindu Kush Himalaya has given rise to the formation of numerous new glacial lakes, which are the major cause of GLOFs.
An “Inventory and Monitoring of Glacial Lakes / Water Bodies in the Himalayan Region of Indian River Basins” found that there are 352, 283, and 1,393 glacial lakes and water bodies in the Indus, Ganga, and Brahmaputra basins respectively.
Do you know?
Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes.
SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional beam-scanning radars.
