Glacial Lakes and Glacial Lakes Outburst Floods (GLOFs) ( UPSC Prelims)

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News Context

The report from the Central Water Commission (CWC) offers insights into Glacial Lake Outburst Floods (GLOFs).

Key Highlights

Among 100 glacial lakes each exceeding 10 hectares, 34 exhibited an increasing trend in water spread area, 20 showed a decreasing trend, and 44 experienced no change in trend.

About Glacial Lake and Glacial Lake outburst flood (GLOFs)

Glacial lakes are bodies of water formed by melting glaciers, typically located at or near the glacier's base. The Indian Himalayan Region (IHR) hosts 11 river basins and 28,000 glacial lakes. There are two primary types of glacial lakes:
  ● Supraglacial lakes: These are formed by meltwater accumulating in depressions on glaciers and are prone to melting during the summer.  
  ● Moraine-dammed lakes: These are created by meltwater at the glacier's toes, dammed by loose debris or ice cores, and are susceptible to sudden failure.  
 GLOFs (Glacial Lake Outburst Floods) occur when there is a sudden and rapid release of water from a glacial lake, often due to the failure of a moraine dam or ice dam. An example is the 2023 South Lhonak GLOF, which damaged the Teesta III Dam in Sikkim.
 Major causes of GLOFs include glacial surging (a rapid short-term advance of a glacier), moraine dam failure, seismic activities, and human activities.

India’s Mitigation Strategy

• The NDMA, through its Committee on Disaster Risk Reduction (CoDRR), focuses on reducing risks.
 • The National Glacial Lake Outburst Flood (GLOF) Risk Mitigation Project (NGRMP) is active in Arunachal Pradesh, Himachal Pradesh, Sikkim, and Uttarakhand.
 • The Central Water Commission (CWC) is responsible for monitoring 902 glacial lakes and water bodies in the Himalayas.
    o 90 GLOF project-based studies have been approved under the National GLOF Risk Mitigation Program (2021-2026).
 • Synthetic Aperture Radar imagery is used to automatically detect changes in the size of glacial lakes.