The recent flash floods in Uttarkashi, Uttarakhand, which occurred on August 5, 2025, have resulted in a devastating situation, with at least 90 people dead and over 50 missing. While the immediate trigger was reported as a cloudburst, the underlying causes are complex and point towards a significant human contribution, according to local residents.

Local Voices Blame Unchecked Construction and Ignored Warnings

Residents of Uttarkashi allege that the disaster in Dharali was, in part, man-made. They claim that unchecked construction within the Bhagirathi Eco-Sensitive Zone (BESZ) and the repeated disregard of their warnings contributed significantly to the scale of the tragedy. Himalayayi Nagrik Drishti Manch, a local collective, submitted a memorandum to the BESZ monitoring committee and various Union ministries, highlighting persistent violations of the BESZ notification. This notification outlines permissible, restricted, and prohibited activities within the 4,179 sq km zone, covering a 100-km stretch of the Bhagirathi River from Gaumukh to Uttarkashi.

Pushpa Chauhan, a social worker and former head of a panchayat near Gangotri, stated that the authorities had been informed about "disaster-causing construction works" in the valley but that their concerns and warnings were repeatedly ignored. The collective emphasized the need for a "disaster-resilient sustainable approach" to development within the BESZ and reminded authorities of the construction ban in river areas, as outlined in the Zonal Master Plan approved in 2020. This plan restricts construction up to 100 meters from the middle of the river. Locals argue that tourism-centric activities have continued unabated in the area, adding anthropogenic pressure on the sensitive environment.

Fragile Geography and Climate Change

The Uttarkashi region's rugged Himalayan topography, geological vulnerability, and the impacts of climate change exacerbate the risks of flash floods. The area's steep slopes, deep gorges, and narrow valleys accelerate rainwater and landslide debris flow, intensifying the impact of flash floods. The region's terrain causes rapid runoff, preventing water from percolating into the ground and instead directing it forcefully into river systems.

Rising temperatures have led to increased melting of glaciers around Gangotri and Yamunotri. This meltwater, combined with rainfall, increases the hydrological load and the likelihood of flash floods. Climate change is causing mountain temperatures to rise faster than the global average, increasing the risk of catastrophic flooding.

Theories on the Trigger

While a cloudburst was initially reported as the cause, scientists are exploring other possibilities, including a glacial lake outburst flood (GLOF), a glacier collapse, or a landslide. ISRO satellite images reveal significant sediment and mudflow deposition near the Bhagirathi and Khera Gad rivers, indicating the scale of the destruction. One theory suggests that a mountain peak blocked moisture-laden clouds, causing heavy rain in the upper areas. Another theory suggests that the mudslide was a reactivated landslide.

Warnings and Aftermath

The India Meteorological Department (IMD) had issued warnings for heavy rainfall in the region prior to the event. Despite these warnings, the flash flood caused widespread destruction, particularly in Dharali village, which lies on the pilgrim route to Gangotri Dham. Houses, shops, and other infrastructure were swept away by the raging torrent. Preliminary assessments suggest that at least 50 hotels were submerged or washed away, along with 40-50 houses.

The disaster disrupted connectivity to Gangotri Dham, impacting the Char Dham Yatra. Rescue operations were launched immediately, with teams from the Indian Army, NDRF, and SDRF mobilized. The Uttarkashi police urged residents and tourists to stay away from the swollen rivers.

Moving Forward

The Uttarkashi flash flood highlights the increasing risk of disasters in ecologically fragile regions. It underscores the need for a disaster-resilient and sustainable approach to development in the Himalayas, with stricter enforcement of environmental regulations and a greater focus on climate change mitigation. Experts call for climate-resilient infrastructure, early warning systems, and a science-backed approach to development to prevent future tragedies.