Himachal's Glacial Lakes Expanded Up to 60% in a Decade, IIT Mandi Study Finds

A study by the Indian Institute of Technology (IIT) Mandi has found that glacial lakes in Himachal Pradesh have expanded by 30% to 60% over the last decade. The researchers examined more than 2,000 glacial lakes and numerous glaciers in the state and identified between 9 and 12 lakes as critical, more than the four lakes flagged by India's National Disaster Management Authority (NDMA).

"There are many aspects to it. The glaciers are melting, and with a rise in tourism, there is carbon and dust deposition. This deposition is enhancing glacial melting," said Dericks P. Shukla, founding chairperson and associate professor at IIT Mandi's School of Civil and Environmental Engineering. He said permafrost — ground that stays below zero degrees Celsius on average for two years — exists in the Himalayan region, and that its melting causes the layer above to move, destabilizing the terrain.

The NDMA has identified four glacial lakes in Himachal Pradesh requiring immediate attention: Ghepan Lake, Vasuki Lake, Kashang Lake, and a lake near Baspa. Based on two types of surveys, IIT Mandi identified between 9 and 12 lakes as critical. Shukla said the greatest danger comes from Ghepan Lake, Yoche and Kali Kund, which are expanding continuously every year; Vasuki Lake is also changing in size, but the absence of human settlements for several kilometers downstream lowers the risk there.

Shukla linked the findings to a disaster in Nepal, where a glacier collapsed into the Lhende Khola river, a tributary of the Bhotekoshi River that flows from China into Nepal, triggering a flash flood on August 26 that killed 1,127 people. He said permafrost melting is also believed to have occurred there, and that increased tourist traffic through mountain tunnels has added pollution and dust that deposit a black layer on glaciers, absorbing energy and accelerating melting.