UPSC Notes

Glacial Lake Outburst Floods (GLOFs)

PYQs

12

Articles

3

Momentum

38

Phase IFoundation

Background

Overview

Critical for understanding natural disasters in sensitive mountain ecosystems, particularly the Himalayas. It links physical geography, climate change impacts, and disaster management, which are core GS1 and GS3 topics.

Glacial Lake Outburst Floods (GLOFs) are sudden releases of large volumes of water from glacial lakes, often caused by the failure of natural dams (moraines or ice) due to factors like glacier retreat, ice avalanches, or seismic activity. These events can lead to catastrophic downstream flooding.

Phase IIStatic core

Facts & tables

Key facts

Causes

Glacier retreat, ice/rock avalanches, seismic activity, extreme rainfall.

Impacts

Catastrophic flooding, destruction of infrastructure (hydropower, bridges), loss of life, damage to settlements.

Vulnerability

Himalayan region with numerous glacial lakes and glaciers is highly susceptible.

Monitoring Challenges

Difficult due to remote, inhospitable terrain; satellite imagery and remote sensing are used but accurate forecasting remains challenging.

Trigger Mechanisms

Landslides, avalanches, seismic activity, or rapid glacial melting.

Himalayan Vulnerability

High concentration of glaciers and glacial lakes, increasing risk due to climate change.

Cross-border Impact

GLOFs in upstream countries can cause devastating floods in downstream nations, necessitating regional cooperation.

Economic Impact

Significant damage to vital infrastructure (hydropower, roads) and loss of life.

Reference table

Static syllabus anchors

TypeReference
Conceptual areaClimate Change & Conventions
Conceptual areaPhysical & Regional Geography
Conceptual areaDisaster Management
Conceptual areaClimate Change Impacts
Conceptual areaHimalayan Ecosystem
Conceptual areaHimalayan Geography

Reference table

Institutions & roles

BodyRole
Indian Space Research Organisation (ISRO)Monitors glacial lakes and glaciers using satellite imagery
National Disaster Management Authority (NDMA)Coordinates disaster response and mitigation efforts in india
Phase IIIExam lens

Prelims angle

Overview

Prelims angle: Factual recall

Prelims angle: Statement-based questions

Quick revision

  • Sudden release of water from glacial lakes.
  • Caused by moraine dam failure, ice/rock avalanches, seismic activity.
  • Increased frequency linked to global warming and glacier retreat.
  • Significant threat to Himalayan infrastructure and settlements.
  • Monitoring challenges due to remote terrain; satellite data used.

High-confidence PYQs

Topic timeline

Climate Change & ConventionsPhysical & Regional GeographyDisaster ManagementClimate Change Impacts

Danger from above: On the Nepal flood

28 Aug 2026 · GLOFs are sudden floods from glacial lakes, often climate-induced, causing widespread destruction in mountainous regions like the Himalayas, posing significant challenges for monitoring and disaster preparedness.

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A shared disaster, beyond borders and geopolitics

29 Aug 2026 · GLOFs are sudden floods from glacial lakes, a major hazard in the Himalayas, intensified by climate change, with severe cross-border socio-economic impacts.

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Nepal disaster: What is a glacier collapse and how does it happen?

29 Aug 2026 · GLOFs are sudden floods from glacial lakes, triggered by events like glacier collapse, posing severe risks to downstream areas, especially in the Himalayas, exacerbated by climate change.

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Related topics

Practice writing on this topic

UPSC has asked 12 linked questions on Glacial Lake Outburst Floods (GLOFs) in Mains. Write an answer to one — and get it evaluated.

UPSC Prelims PYQs on Glacial Lake Outburst Floods (GLOFs)

Practice official previous year questions asked by UPSC related to this concept.

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