Close to 60 per cent of the proposed 275 km long Manali-Leh strategic rail link lies in areas that face moderate to high risk from natural hazards, a new study has said while stressing the need for extensive geotechnical and cryospheric investigation to mitigate the threat of climate-induced disasters.
The study revealed that 7.96 per cent of the area is under a very high susceptibility zone, 20.28 per cent area is under a high susceptibility zone and 29.32 per cent area is under moderate susceptibility zone, with 42.44 per cent area falling in the low and very low susceptibility zone.
“The results suggest that a significant portion of the railway line will pass through moderate to high hazard-prone regions, which emphasizes the need for detailed geotechnical and cryospheric investigation before construction,” the researchers said.
“The analysis also revealed that several important stations, such as Chhuchot, Phe Yard, Debring, She Road and Darcha, are located within high susceptibility zones.”
Located in a complex geological terrain and experiencing extreme climate events frequently, the region is particularly vulnerable to various cryospheric hazards such as permafrost-induced landslides, avalanches and glacial lake outburst flood (GLOF), according to the study.
Additionally, the railway line will be constructed in the permafrost regions, which leads to ground instability and damage to infrastructure.
Undertaken by three researchers from the School of Civil and Environmental Engineering, Indian Institute of Technology, Mandi, the study was published in Elsevier’s Geodesy and Geodynamics, a peer-reviewed journal, on October 30.
The researchers marked a 20 km wide study zone along the length of the line and employed nine conditioning factors such as elevation, slope, permafrost zonation index, distance to glaciers, distance to glacial lakes, distance to rivers, distance to lineament, lithology and geomorphology.
The elevation in the study area ranged from 6,870 feet near Manali to 21,000 feet in Ladakh, with temperatures ranging from about 35 degrees Celsius during summer to below minus 28 degrees Celsius during winter.
These extreme environmental conditions make the region highly susceptible to cryospheric hazards that may threaten transportation infrastructure.
The Leh-Manali corridor is one of the most strategically important transportation routes in the Indian Himalayas and the existing Leh-Manali Highway serves as a crucial link between Ladakh and Himachal Pradesh, supporting military logistics, local livelihoods, trade and tourism.
However, the corridor traverses glacierised terrain, permafrost-affected slopes, steep valleys and high mountain passes, making it highly vulnerable to cryospheric hazards.
In response to the growing transportation demand and strategic importance of the region, the Government of India has proposed the Bilaspur–Manali–Leh railway project, which is expected to become one of the highest railway systems in the world. This line is approximately 275 km, of which about 121 km consists of open sections and 154 km comprises 62 tunnels.
The alignment passes through several key locations, including Sissu, Keylong, Darcha, Sarchu, Pang, Tanglang La Pass, Upshi, and Leh, with a total of 15 proposed railway stations distributed along the corridor.
“While this railway will significantly improve regional connectivity and socio-economic development, its long-term stability may be affected by cryosphere-related hazards and climate-induced landscape changes,” the researchers said.
The Himalayan region, often referred to as the “Third Pole”, contains the largest concentration of ice and snow outside the polar regions and plays a critical role in sustaining water resources and ecosystems across Asia, the study observed.
“However, rapid climate warming has accelerated glacier retreat, permafrost degradation, snow cover variability, and glacial lake expansion, increasing the occurrence of cryospheric hazards such as GLOFs, avalanches, debris flows and thaw-induced slope failures.
These hazards pose significant threats to mountain communities, ecosystems, and critical infrastructure, particularly transportation networks located in high-altitude environments,” the researchers said.
