A temporary lake formed near Harsil, Uttarakhand, poses a new and significant risk to the surrounding areas, prompting urgent evaluations and mitigation efforts. The lake was created after a flash flood on August 5, 2025, when a massive accumulation of muck, debris, and uprooted trees carried by the Khirgad stream blocked the natural flow of the Bhagirathi River. This blockage led to the formation of a kilometer-long water body, resembling a lake, near Harsil village. The sudden development has raised serious concerns about potential flooding downstream, endangering the lives and livelihoods of local residents.
The Uttarakhand State Disaster Management Department reported that the Khirgad rivulet deposited approximately 30 feet of debris into the Ganga riverbed, contributing to the formation of the temporary lake. Continued rainfall in the upper reaches of Gangotri has further exacerbated the flood risk, leading authorities to evacuate residents from riverside homes to safer, higher locations. The Uttarakhand State Emergency Operation Centre (SEOC) issued a statement explaining that the debris dam has elevated the Ganga's water level. Teams from the Indian Army and the Irrigation Department are working to divert the excess flow.
The incident occurred in the aftermath of a cloudburst that triggered a flash flood in the Kheer Ganga catchment area, devastating villages such as Dharali. The deluge swept away homes, shops, local markets, roads, and hotels, leaving many people missing and presumed trapped under debris. Initial reports suggested a cloudburst as the primary cause, but scientists analyzing rainfall data and satellite imagery have proposed that a glacial lake outburst flood (GLOF) or a glacier collapse may have been the more direct trigger. Data indicated that the rainfall in Harsil and surrounding areas was not significant enough to cause such severe flooding, pointing towards a sudden release of water from a glacial source. Satellite images revealed the presence of glaciers and glacial lakes situated above the affected site, reinforcing the possibility of a GLOF.
The formation of the lake has submerged the Harsil helipad and disrupted the river's natural flow. Chief Minister Pushkar Singh Dhami emphasized the need to drain the lake to ensure the safety of locals and has directed officials to take all necessary steps to prevent further risk. While water is being drained from the lake, residents have warned that heavy upstream rain could sharply increase the risk of overflow. The district administration is closely monitoring the situation, with teams on the ground working to clear the blockage and maintain a steady water discharge. Uttarkashi District Magistrate Prashant Arya has instructed officials to ensure uninterrupted outflow and to relocate residents living along the riverbank to safer locations, providing them with necessary relief materials.
Rescue operations are underway to locate those still missing after the initial flash flood. Approximately 150 Army personnel, along with SDRF teams and local ITBP units, are conducting search-and-rescue operations. Additional Army columns with tracker dogs, drones, and earthmoving equipment have been deployed to Harsil. The Indian Army, Air Force, and other agencies are involved in the relief efforts. The government has announced financial assistance of Rs 5 lakh for affected families and is working to restore road connectivity and distribute essential supplies.
The temporary lake near Harsil presents an ongoing threat that requires constant monitoring and proactive measures. The combined efforts of the local administration, the Indian Army, and disaster management agencies are crucial to mitigating the risks and protecting the lives and property of the residents in the downstream areas.
