Indian Space Research Organisation (ISRO) tracks notable expansion of glacial lakes in Indian Himalayas

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As per ISRO, long-term satellite imagery covering the catchments of Indian Himalayan river basins from 1984 to 2023 indicates significant expansion of glacial lakes.
- Indian Himalayas are often called Third Pole because of extensive glaciers and snow cover.
- Satellite remote sensing technology is crucial for understanding glacier retreat rates, assessing Glacial Lake Outburst Floods (GLOF) risks, and gaining insights into climate change impacts.

Key observations
- Glacial Lake is a body of water that originates from melting of glacier.
- Based on their formation process, they are grouped into four broad categories, namely
  - Moraine-dammed (water dammed by moraine), Ice-dammed (water dammed by ice), Erosion (water dammed in depressions formed by erosion), and other glacial lakes.
  - Material, usually soil and rock, left behind by moving glacier is called Moraine.
- Of the 2,431 lakes, 676 glacial lakes have expanded since 1984. 130 of these lakes are situated within India in Indus, Ganga, and Brahmaputra River basins.
  - Among 676 expanding lakes, majority of them are Moraine-dammed followed by Erosion dammed glacial lakes.
- Glacial lakes are freshwater sources for rivers in Himalayan region. However, they also pose significant risks like GLOFs.

GLOFs occur when glacial lakes release large volumes of melt-water due to failure of natural dams, such as those made of moraine or ice, resulting in sudden and severe flooding downstream.
- These dam failures can be triggered by various factors, including avalanches of ice or rock, extreme weather events like global warming, earthquake etc.
GLOFs are recognized as a potential climatological disaster in National Disaster Management Plan 2019 of India.