ISRO Study Warns of Potential Glacial Flood Disaster in Lahaul-Spiti

A joint study by the National Remote Sensing Centre of ISRO (NRSC-ISRO) and the Himachal Pradesh State Disaster Management Authority (HPSDMA) has warned of a possible Glacial Lake Outburst Flood (GLOF) in Himachal Pradesh’s Lahaul-Spiti district, posing a major threat to 34 downstream settlements, including the tourist village of Sissu.

The study revealed that Ghepan Lake, a moraine-dammed glacial lake located at an altitude of around 13,580 feet, has expanded nearly threefold over the past three decades. Its size increased from 36.49 hectares in 1989 to 101.30 hectares in 2022 due to accelerated glacier melting linked to climate change and rising temperatures in the Himalayas.

Researchers warned that continued glacier retreat and erratic weather conditions are destabilising the lake, which is held back by a fragile barrier of rocks, sand and glacial debris. Experts fear that heavy rainfall, avalanches, landslides or glacier collapse could trigger a sudden breach, unleashing a devastating flood downstream.

Sissu village, situated around 11 kilometres from the lake, has been identified as the most vulnerable area and placed in the highest-risk red zone in the study.

“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,” Lahaul and Spiti Deputy Commissioner Kiran Bhadana told PTI on Wednesday.

She said the district administration is coordinating with the National Disaster Management Authority (NDMA) and the Centre for Development of Advanced Computing (C-DAC) to map the potential flood impact zone and strengthen preparedness measures.

Bhadana emphasised that evacuation remains the only effective response during a GLOF event.

“We need to train people to deal with such a situation because floodwaters could reach Sissu within 20 minutes,” she said, adding that local residents are being trained for emergency evacuation and disaster response.

Officials said the administration has already begun installing early warning systems and preparing communities to minimise casualties in the event of a disaster.