India
oi-Madhuri Adnal
The deadly floods in Nepal have brought fresh attention to a similar danger in India, where 195 glacial lakes have been identified as high-risk under the National GLOF Risk Mitigation Programme.
The concern comes after floods and debris buried parts of Devighat in Nepal’s Nuwakot district. India has identified around 7,500 glacial lakes across the Himalayan region, with 195 considered high-risk and prioritised for monitoring, early warning and mitigation.
India has identified 195 high-risk glacial lakes under its National GLOF Risk Mitigation Programme for monitoring and mitigation, following Nepal’s deadly floods and Sikkim’s October 3, 2023, Glacial Lake Outburst Flood (GLOF) event.
Sikkim accounts for about 10% of India’s glacial lakes, including 25 classified as very high-risk. The Ganga river basin has around 4,700 glacial lakes and covers a catchment of more than 2.5 lakh square kilometres.
Why Glacial Lakes Can Be Dangerous
A Glacial Lake Outburst Flood (GLOF) happens when water from a glacial lake is suddenly released. An avalanche, landslide, rockfall, ice collapse or heavy rain can trigger it. A weakened moraine dam holding the lake can also give way.
Once the water starts moving, it can carry rocks, mud, trees and other debris downhill, turning into a destructive torrent.
The risk is especially serious in the Himalayas, where settlements and major infrastructure such as roads, bridges, hydropower projects and security installations are often located along narrow river valleys.
Sikkim’s 2023 Disaster Showed The Risk
India experienced the force of a GLOF on October 3, 2023, when South Lhonak Lake in Sikkim burst following a massive slope failure.
Official assessments said a large amount of glacial material and rock collapsed into the lake around midnight, creating a displacement wave estimated at about 20 metres.
The resulting flood swept through the Teesta basin, damaging settlements and hydropower infrastructure.
The disaster also showed why keeping an eye only on rainfall and river levels is not enough. A sudden collapse of ice or rock at high altitude can set off a chain reaction, leaving people downstream with very little time to respond.
What India Is Doing About The 195 Lakes
The National GLOF Risk Mitigation Programme has placed 195 high-risk glacial lakes under focused action. The programme covers five areas: assessment, monitoring, early warning, mitigation and community awareness.
Krishna Vatsa, a member of the National Disaster Management Authority, said the Nepal disaster was a reminder of how quickly one hazard can lead to another.
“These are cascading hazards: an ice or rock failure can become a debris flow, create a temporary lake and then generate a flash flood. Such events can develop extremely rapidly and may provide very little warning time downstream,” he said.
Following the 2023 Sikkim disaster, the Centre set up a high-level coordination committee on GLOF risk reduction, headed by Prime Minister’s Principal Secretary P K Mishra.
The Centre also allocated Rs 150 crore for the National GLOF Risk Mitigation Programme in four Himalayan states with high-risk glacial lakes.
Multi-agency teams involving the NDMA, Central Water Commission, Geological Survey of India, Centre for Development of Advanced Computing, Indo-Tibetan Border Police and the Army were sent to assess “A-category” lakes.
Early Warning Remains The Biggest Challenge
Finding the 195 high-risk lakes is only part of the job. The bigger challenge is monitoring them reliably in some of the most difficult terrain in the country.
Heavy snowfall, landslides, extreme weather and poor connectivity can affect monitoring equipment and communication systems. A warning is useful only if it reaches people downstream quickly enough for them to move to safety.
That includes villages, hydropower projects, district authorities and security installations.
Syed Safi Ahsan Rizvi, a former NDMA member, said the national programme needs to be expanded and implemented faster.
“India’s National GLOF Risk Mitigation Programme has marked 195 at-risk glacial lakes and follows five key priorities (assessment, monitoring, early warning, mitigation, community awareness). It needs to be speeded up and scaled up immediately as a priority for national security,” he said.
The high-level coordination committee held its first meeting in November 2024. However, details on the progress of individual lakes and work carried out on the ground remain limited in the public domain.
For communities living below these lakes, preparation needs to go beyond identifying the danger. Warning systems, evacuation routes, updated hazard maps and emergency plans need to work when they are actually needed.
The floods in Nepal have once again shown that the threat from glacial lakes is not a distant possibility. For India, the challenge now is ensuring that its 195 high-risk lakes are properly monitored and that warnings can reach vulnerable communities before a sudden release of water turns into a disaster.
