Himachal Pradesh's Sissu sits on ‘time bomb’ as expanding glacial lake threatens 34 settlements

Shimla: Sissu, a popular tourist village in Himachal’s Lahaul and Spiti, is sitting on a time bomb as the expanding Ghepan Lake in the district could inundate 34 downstream settlements, a study has warned.

A joint study conducted by the Himachal Pradesh State Disaster Management Authority (HPSDMA) and the National Remote Sensing Centre of ISRO (NRSC-ISRO) has revealed that the size of Ghepan Lake has increased nearly threefold over the last three decades, from 36.49 hectares in 1989 to 101.30 hectares in 2022.

Scientists attribute the lake expansion to accelerated melting of glaciers, triggered by climate change, and rising temperatures in the Himalayas. Further glaciers melting and changing weather patterns are making the lake unstable, the research stated, warning of a potentially devastating Glacial Lake Outburst Flood (GLOF) in the region.

The threat looms large for over 34 downstream settlements, including Sissu, as the moraine-dammed glacial lake is held back by a fragile natural barrier of rocks, sand and glacial debris at an altitude of about 13,580 feet, the study said.

According to the report, Sissu village, located about 11 kilometres downstream from Ghepan Lake, is the most vulnerable settlement and is placed in the red zone (highest risk zone).

"The threat perception is very real, and an early warning system has been installed at Sissu Lake. Based on its response, this system will also be installed at Ghepan Lake," Deputy Commissioner, Lahaul and Spiti, Kiran Bhadana told the PTI on Wednesday.

"We are already working in close coordination with the National Disaster Management Authority (NDMA) and the Centre for Development of Advanced Computing (C-DAC) and are establishing the high flood line to determine the impact area," she said.

Bhadana further stressed the need to train the locals to deal with the such disaster.

"There is no mitigation in times of GLOF, there is only evacuation. I spoke to the Special Secretary Disaster Management today ( May 27) and urged that we need to train people to deal with a GLOF-like situation so they can escape and be evacuated as the floodwaters would reach Sissu in 20 minutes", she said.

“The district administration is training people because the Glacial Lake Outburst Flood would submerge a huge area of the district,” she said, and added, "I have been told that I am the first Deputy Commissioner in the country to get an early warning system for GLOF".

Experts have cautioned that heavy rainfall, avalanches, landslides, or the collapse of glacier masses could trigger a catastrophic flood downstream.