Sikkim Identifies 40 High-Hazard Glacial Lakes

Key facts

• The eastern Himalayan state of Sikkim has identified 40 high-hazard glacial lakes, with 16 of them classified as being at the highest risk of catastrophic outbursts that could threaten downstream settlements.
• Glacial lakes are formed by the melting of glaciers and accumulation of meltwater in depressions on or near the glacier's surface.
• GLOFs occur when these lakes suddenly burst open due to factors such as excessive water accumulation or triggers like earthquakes.
• One such outburst in Sikkim in October 2023 resulted in at least 60 fatalities and extensive damage in the Mangan, Gangtok, Pakyong and Namchi districts.
• Of the 40 high-hazard lakes, 16 are in Category A (highest risk), two in Category B (high risk), nine in Category C (moderate to low risk) and 13 remain unclassified.
• Sikkim's Department of Science and Technology was designated the nodal department for GLOF hazard assessment and mitigation studies in February 2025.
• The Sikkim government has identified Shako Chho as most vulnerable to GLOF.