GLACIAL LAKE OUTBURST FLOOD (Syllabus: GS Paper 2 – Geography/Disaster)

News-CRUX-10     6th October 2023        
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Context: Recently, Recently, in the journal Nature Communications, the first global assessment by an international team revealed that India and Pakistan together account for a third of the world's population exposed to Glacial Lake Outburst Floods (GLOFs). It emphasized that the risk of GLOFs increases with distance from a glacial lake.

Glacial Lake Outburst Floods (GLOFs)

  • About: Glacial Lake Outburst Flood (GLOF) is a type of flood that occurs when a glacier-contained water body is suddenly released.
  • Causes of GLOF: GLOFs happen when the natural dam formed by a glacial lake fails, allowing the stored water to flow rapidly.
  • Formation of Proglacial Lakes: Retreating glaciers, especially in regions like the Himalayas, often create proglacial lakes. These lakes are typically held in place by sediments and boulders.
  • Breaching Boundaries: If the boundaries of these proglacial lakes are breached, a significant volume of water rushes into nearby streams and rivers. This rushing water picks up sediments, rocks, and other debris, causing downstream flooding.


Key GLOF Features

  • They involve sudden and sometimes cyclic water releases.
  • GLOFs are typically rapid events, lasting for hours to days.
  • They result in a substantial increase in downstream river discharge, often by an order of magnitude.

Glaciers

  • Formation: Glaciers begin as fallen snow that gradually compresses into thickened ice masses over time. This transformation occurs when snow accumulates and remains in one place for an extended period.
  • Distribution: Glaciers can be found on every continent except Australia, with some of them dating back hundreds of thousands of years.
  • Himalayan Glaciers: A significant concentration of glaciers is situated in the Himalayas, which span India's extensive northern border.
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