Glacial Lakes Expansion and GLOF Risk (Geography)
Glacial Lakes Expansion and GLOF Risk (Geography)
Why In News:
A study finds that four glacial lakes in Arunachal Pradesh have expanded significantly over the past decade, driven by accelerated glacial melt due to climate change.
This raises acute concern about Glacial Lake Outburst Floods (GLOFs) threatening downstream communities and infrastructure.
What Are Glacial Lakes?
Formation: Form when meltwater collects in depressions created by glacial erosion, often dammed by moraines (ridges of glacial debris).
Why Expanding: Rising temperatures accelerate glacial melt, increasing water volume and forming new lakes.
Glacial Lake Outburst Floods (GLOFs)
Definition: Sudden release of water from a glacial lake, typically caused by moraine dam failure, ice dam collapse, or an avalanche or earthquake triggering overflow.
Destructive Potential: A single GLOF can release millions of cubic metres of water within minutes, devastating valleys, villages, roads, and hydropower projects downstream.
India's Exposure: Arunachal Pradesh, Himachal Pradesh, Uttarakhand, Sikkim, and Jammu and Kashmir are most vulnerable.
Sikkim GLOF (2023): South Lhonak Lake outburst in October 2023 caused catastrophic destruction including the Teesta-III hydropower dam.
Institutions
NDMA: National Disaster Management Authority has issued GLOF management guidelines covering early warning, land-use planning, and emergency response.
ICIMOD Warning (2019): Hindu Kush Himalaya Assessment warned that even limiting warming to 1.5 degrees C will result in the loss of one-third of Himalayan glaciers by 2100.