Expanding Glacial Lakes Increase GLOF Risks In Arunachal Pradesh

Context: The article examines the expansion of glacial lakes in the Mago Chu basin and the resulting need for dynamic monitoring, early warning and transboundary Himalayan cooperation.

Source: “How glacial lake expansion adds to the growing concerns about GLOFs,” The Indian Express, July 21, 2026.

Core Points

• Four of five monitored lakes in the Mago Chu basin of Tawang expanded between 2016 and 2026.
• Sanhapo, classified as a high-risk lake, expanded from 55.87 hectares in 2016 to 88.81 hectares by June 2026.
• Two unnamed lakes in the basin have been placed in the “very high risk” category.
• Rising temperatures accelerate glacier retreat and meltwater accumulation, but lake size alone does not determine GLOF probability.
• Moraine dams can consist of poorly consolidated sediment, making them vulnerable to erosion, seepage and sudden failure.
• Ice or rock avalanches can create displacement waves that overtop a natural dam. Extreme rainfall, earthquakes and permafrost degradation can also increase instability.
• GLOFs can damage settlements, roads, bridges, hydropower facilities and river ecosystems far downstream.
• Risk assessment must combine lake expansion with dam condition, slope stability, downstream exposure and possible triggering events.
• Satellite monitoring, field validation, automated sensors, evacuation planning and transboundary data-sharing are required because many Himalayan lakes lie outside India’s borders.

Prelims Relevance

• A GLOF is a sudden release of water from a glacier-associated lake. Read More.
• Glacial lakes may be moraine-dammed, ice-dammed or situated in depressions created by glacial erosion.
• Moraines are accumulations of rock and sediment transported or deposited by glaciers.
• Mago Chu lies in Tawang district of Arunachal Pradesh within the Brahmaputra river system.

Mains Relevance

• GS I: Himalayan geomorphology and changes in critical geographical features.
• GS III: Climate adaptation, disaster management, remote sensing and transboundary risk.

Supporting Fact Box

• ISRO identified 2,431 Himalayan glacial lakes larger than ten hectares in 2016–17; 676 had expanded significantly compared with their 1984 extent.
• Among the 676 expanding lakes, 307 were moraine-dammed, 265 erosion-formed and eight ice-dammed.
• Satellite monitoring provides repeat observations over inaccessible terrain but cannot fully replace field inspection of dams and downstream conditions.
• The National GLOF Risk Mitigation Programme has an approved outlay of ₹150 crore.