Muguthang, December 4, 2024 –
Expedition Team Explores Glacial Flood Mitigation at Lhonak Valley
With accelerating global warming, glaciers are retreating at unprecedented rates, leaving behind high-risk glacial lakes that could burst and unleash catastrophic floods. In Sikkim alone, 40 glacial lakes have been identified as high-risk by the Government of India. Can glacial floods be mitigated or their impact reduced? Seeking answers to this pressing questions, a multidisciplinary expedition team embarked on a seven-day mission to the Lhonak Valley. Their focus: to assess whether the destructive impact of glacial floods can be mitigated and explore the feasibility of innovative flood control measures.
Muguthang, North Sikkim
The team investigated the aftermath of the 2023 glacial flood in the Lhonak Valley to uncover whether its behavior aligned with typical patterns of glacial floods—high-velocity torrents carrying debris, sediment and boulders with massive destructive potential. In a significant finding, the team observed that the flood slowed down dramatically as it passed through the widened valley sections at Goma and Dolma Sampa. This natural dissipation of force caused debris deposition, reducing the flood’s destructive impact downstream. It was only below Dolma Sampa that the flood picked up momentum and debris causing widespread devastation downstream. The team also analyzed the subsurface geology at Dolma Sampa and measured the discharge of the Lhonak River. These insights will be crucial in evaluating the feasibility of a retention structure at Dolma Sampa, which could regulate floodwaters and protect downstream infrastructure.
The expedition brought together experts in geology, ecology, engineering, hydrology, and remote sensing from the Department of Science and Technology, Department of Mines and Geology, and the National Disaster Management Authority. The team endured freezing temperatures of minus 10 degrees centigrade and high winds while camping in Muguthang at 14,000 feet to conduct their studies.
The team is set to return to Gangtok on December 5, 2024, carrying critical data and insights that will inform future strategies for managing glacial flood risks. Their findings will form the basis of a concept note, which will undergo wider consultation and feasibility assessments.
This initiative marks the fourth glacial lake expedition by the Government of Sikkim, aimed at building resilience to safeguard lives, livelihoods, critical infrastructure, and the environment.
