Scientists suspect an avalanche caused Wednesday's devastating Bhotekoshi flood.

At least hundreds died when a sudden torrent of water rushed down the Bhotekoshi river in Nepal's Rasuwa district early Wednesday. Hundreds of others are still missing after the surging waters destroyed bridges and infrastructure near the Rasuwagadhi border crossing. Rescue teams have recovered bodies across several districts, including Nuwakot, Dhading, Chitwan, Tanahun, Gorkha, and Nawalparasi East. This disaster echoes past tragedies in the Himalayan region, where melting glaciers pose increasing risks to downstream communities.

Triggers behind the Tragedy

Initial satellite imagery suggests a massive ice-and-rock avalanche blocked the Lhende river, a tributary along the Nepal-China border. This blockage created a temporary dam. When the dam failed, it released a massive wave of mud, boulders, and water into the Bhotekoshi river. A 4.4 magnitude earthquake also struck Tibet shortly before the flood, though scientists have not yet confirmed if the tremor caused the avalanche. The International Centre for Integrated Mountain Development (ICIMOD) noted the flood's unusual speed and power. Water levels in the Trishuli river at Galchhi spiked by nine metres within 30 minutes, while Malekhu saw a seven-metre rise.

Lingering Threats and Border Concerns

Experts warn the danger has not passed. Satellite observations, hindered by cloud cover, are ongoing to assess if other temporary lakes have formed upstream. Past incidents, like the July 2025 glacial lake outburst on the Lhende river, highlight the area's vulnerability. A joint study by ICIMOD and the UN previously identified 47 potentially dangerous glacial lakes across Nepal, India, and Tibet, with 21 in Nepal alone.

Meanwhile, Chinese authorities report a new, large barrier lake forming downstream near the confluence of the Chotchen and Purupe Tsangpo rivers in Tibet. With two million cubic metres of water already accumulated and an estimated three million more expected soon, there are serious concerns about another dam failure. Chinese monitoring teams are running flood simulations and preparing emergency responses.

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Bhotekoshi Floods