The Lahaul-Spiti administration in Himachal Pradesh has intensified preparations for a possible glacial lake outburst flood (GLOF) from Ghepan Lake. Officials have identified 32 residential areas between Sissu and the Sansari border that could face risks along the possible flood path. A total of 128 locations have also been marked as potential flood-prone zones. The move follows growing concern over the rapid expansion of Ghepan Lake in recent decades.

Ghepan Lake is located at an altitude of 4,070 metres, around 11 km from Sissu. The lake expanded by 178% between 1989 and 2022. Its area increased from 36.5 hectares to 101.3 hectares in 13 years. The possible downstream flood path stretches for nearly 90 km through Udaipur and up to the district boundary.

Lahaul-Spiti deputy commissioner and District Disaster Management Authority chairperson Kiran Bhadana said the Indian Space Research Organisation (ISRO) had alerted the district administration about the lake's expansion in November 2023. ISRO also advised the administration to take precautionary measures to deal with the potential risk.

The administration is now carrying out 'highest flood level' (HFL) markings under the National Disaster Management Authority. These markings will create permanent reference points to show how high floodwaters could potentially rise in vulnerable areas.

Officials also plan to install an early warning system at Ghepan Lake this month. The Centre for Development of Advanced Computing (C-DAC), Thiruvananthapuram, will set up the system. It will monitor the lake's water level and other important parameters and issue alerts when necessary. Authorities successfully tested a similar system at Sissu Lake in April.

A five-member Geological Survey of India (GSI) team will also conduct a 14-day study of the Ghepan Lake area. The team will assess the lake and its surrounding areas. It will measure the lake's depth and water flow and study local meteorological conditions. The team will also examine areas that could be vulnerable to avalanches and landslides.

The district administration will send another team to assess the lake's current condition. Ghepan Lake is around 2,464 metres long and 625 metres wide at its widest point near the glacial snout. Officials estimate that the lake contains more than 35 million cubic metres of water, making any sudden release of water a major concern for downstream areas.

Authorities have also formed rapid response teams in Sissu and Shashin villages. Residents living in vulnerable areas are being trained in disaster preparedness and response measures. The administration is focusing on improving local readiness so that residents can respond quickly if a GLOF occurs.

The district is also constituting a GLOF Monitoring Committee at the district level. The committee will include officials from various departments, experienced mountaineers and other experts. It will conduct regular field inspections and assess risks linked to loose rocks, unstable terrain and other hazards around the lake and its downstream route.

The growing number of glacial lakes across Himachal Pradesh's river basins has raised concerns over GLOF risks. According to a report by the Himachal Pradesh State Centre on Climate Change, the Satluj, Beas, Ravi and Chenab river basins together had 1,619 glacial lakes in 2022. The administration's latest measures at Ghepan Lake aim to strengthen early warning, monitoring and emergency response systems before any possible flood event.