UPSC Notes

Glacial Lake Outburst Floods (GLOFs) and Mountain Hazards

PYQs

7

Articles

1

Momentum

19

Phase IFoundation

Background

Overview

Understanding GLOFs is crucial for disaster management, climate change adaptation strategies, infrastructure planning in mountainous regions, and assessing environmental vulnerabilities in the Himalayas. It integrates physical geography, environmental science, and public policy.

Glacial Lake Outburst Floods (GLOFs) are sudden and rapid releases of large volumes of water from glacial lakes, often triggered by events such as ice or rock avalanches, seismic activity, or extreme weather, leading to devastating downstream impacts. These events are a significant natural hazard in high-altitude, glaciated regions like the Himalayas.

Phase IIStatic core

Facts & tables

Key facts

Formation

Glacial lakes form when meltwater from glaciers is impounded by moraine dams (debris left by glaciers) or ice dams.

Triggers

Common triggers include ice/rock avalanches falling into the lake, rapid melting of ice dams, seismic activity, or heavy rainfall causing moraine dam failure.

Impact

Can cause catastrophic flash floods, destroying infrastructure, agricultural land, and leading to loss of life downstream.

Vulnerability

The Himalayan region is highly vulnerable due to numerous glacial lakes, active tectonics, and increasing glacier retreat due to climate change.

Reference table

Static syllabus anchors

TypeReference
Conceptual areaPhysical & Regional Geography
Conceptual areaClimate Change & Conventions
Conceptual areaIndian Hydrography & Water Bodies

Reference table

Institutions & roles

BodyRole
National Disaster Management Authority (NDMA)Formulates policies and guidelines for disaster management, including glofs
Geological Survey of India (GSI)Conducts geological surveys and hazard assessments in mountainous regions
Phase IIIExam lens

Prelims angle

Overview

Prelims angle: Statement-based questions

Prelims angle: Conceptual understanding

Quick revision

  • GLOFs: sudden release of water from glacial lakes.
  • Triggers: ice/rock avalanches, seismic activity, moraine dam failure.
  • Himalayan vulnerability: numerous lakes, climate change, tectonics.
  • Impacts: flash floods, infrastructure damage, loss of life.
  • Relevance: disaster management, climate adaptation, regional planning.

High-confidence PYQs

Topic timeline

Physical & Regional GeographyClimate Change & ConventionsIndian Hydrography & Water Bodies

Did an ice-rock avalanche originating from a high-altitude area trigger the Trishuli flash flood?

27 Aug 2026 · GLOFs are sudden floods from glacial lakes, often triggered by avalanches, posing a major hazard in the Himalayas due to climate change and geological instability.

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Current topic

Glacial Lake Outburst Floods (GLOFs) and Mountain Hazards

Practice writing on this topic

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UPSC Prelims PYQs on Glacial Lake Outburst Floods (GLOFs) and Mountain Hazards

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