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

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.