Nepal Tragedy Puts Himachal’s Glacial Lakes Under Fresh Scrutiny
Chandratal lake Spiti
Shimla: August 28
The catastrophic glacier-related floods in Nepal and Tibet, which have killed hundreds and left more than a thousand people missing, have put Himalayan states on heightened alert over the growing threat of glacial disasters.
In Himachal Pradesh, the focus has once again turned to vulnerable glacial lakes in Lahaul-Spiti and Kinnaur, with continuous surveillance and early-warning preparedness assuming greater urgency. The issue has also been highlighted by Himachal Scape.
One of the most serious concerns is Ghepan Ghat Lake in Lahaul-Spiti, whose area increased from 36.49 hectares in 1989 to 101.30 hectares in 2022—an expansion of about 178 per cent. A joint HPSDMA-NRSC study has identified 34 downstream settlements as vulnerable, with Sissu among the areas facing the highest risk.
The assessment indicates that in a worst-case GLOF scenario, a flood wave could reach Sissu in only about 21 minutes, with extreme flow velocity and flood depths. The danger could be compounded by boulders, rocks, ice and other debris carried downstream.
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The state has already undertaken detailed bathymetric surveys of other vulnerable lakes. The Vasuki and Sangla glacial lakes, located in Kullu and Kinnaur respectively, have expanded over the past seven years and have been brought under early-warning surveillance. The Vasuki lake area increased from 10.36 hectares in 2017 to 13.38 hectares in 2024, holding about 2.166 million cubic metres of water, with a maximum depth of 36.91 metres.
The Sangla lake, meanwhile, measured 15.73 hectares in a September 2024 survey and contains approximately 1.527 million cubic metres of water. Scientists have warned that a potential outburst could affect the JSW Baspa hydropower project and downstream settlements in the Sangla region.
The Himachal Pradesh State Disaster Management Authority lists dedicated geological and bathymetric surveys for Vasuki and Sangla, besides the GLOF risk assessment of Ghepan Ghat, underscoring the seriousness with which the state is treating the emerging threat.
The Nepal disaster has demonstrated how rapidly a Himalayan glacier-related event can turn into a mass-casualty disaster. Experts are therefore calling for continuous satellite surveillance, annual field inspections, real-time early-warning systems, downstream hazard mapping and evacuation preparedness.
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With glaciers retreating and high-altitude lakes expanding under a warming climate, the threat is no longer a remote possibility. For Himachal, preparedness around vulnerable lakes in Lahaul-Spiti and Kinnaur has become an immediate disaster-management priority.
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