Bhote Koshi Flash Flood, 26 August 2026: What Happened in Nepal’s Rasuwa District

A sudden, violent flash flood tore down the Bhote Koshi River from Tibet into Nepal's northern border district of Rasuwa on the morning of 26 August 2026, sweeping away villages, roads, bridges and hydropower plants along the frontier and downstream. Bagmati Pradesh Police said at least 95 people were confirmed dead in Nepal as the toll climbed through the day, while hundreds more were initially reported missing and were still being accounted for as this article was published.

The disaster struck one of the most sensitive points on Nepal's map: the Rasuwagadhi border crossing with Tibet, the gateway to the Langtang trekking region, and a corridor of hydropower projects that feed Nepal's national grid. Figures were rising and being revised through the day; the numbers below are as reported on 26 August and attributed to the authorities who released them.

What happened, and when

According to reports, the surge originated roughly 25 kilometres inside Tibet and came down the Bhote Koshi at around 09:00 local time, with the maximum flooding channelled through the Lhende Khola, a Bhote Koshi tributary. The water hit the border zone around Rasuwagadhi on the Nepali side and Gyirong (Kerung) Port on the Tibetan side, damaging the "Miteri" Friendship bridge that carries Nepal's main overland trade with Tibet.

From the border the flood ran through the Rasuwa settlements of Timure and Syabrubesi, then continued downstream into Nuwakot and Dhading via the Trishuli River, with damage reported at Betrawati, Trishuli (Bidur), Dhunge, Devighat and Dhunche. The Bhote Koshi feeds the Trishuli, which ultimately joins the Ganges — so the water's path traced a line from a glacier basin on the Tibet frontier down into the populated middle hills.

The human toll

Nepal Police spokesman Abi Narayan Kafle, speaking for the Bagmati Pradesh Police, said at least 95 people were confirmed dead. Earlier tallies through the morning had been far lower — reports cited 8, then 31, then 72 — because the toll rose steadily as rescue teams reached cut-off communities.

The number of missing was harder to pin down. The Nepal Tourism Board's preliminary count put 384 people unaccounted for — 291 foreign nationals and 93 Nepali nationals — with those listed including citizens of India, the United States, the United Kingdom and Malaysia. India accounted for the largest group, with reports of around 105 Indian nationals plus 37 overseas Indians (NRIs). South Korea said eight of its citizens, hydropower workers, were missing and ten more were stranded. Nine Armed Police Force personnel stationed at the Timure border outpost were also reported missing.

Across the border, in Tibet

The flood also caused what Chinese authorities described as "major casualties" at Gyirong Port on the Tibetan side. Chinese state news agency Xinhua reported three people dead and 265 missing across the border. As on the Nepali side, those were the figures released on 26 August and were subject to revision.

Power and infrastructure

The Bhote Koshi–Trishuli corridor is one of Nepal's most important hydropower valleys, and the flood cut straight through it. The Nepal Electricity Authority said around 430 MW of production, transmission and distribution capacity was damaged, naming six facilities.

Roads, bridges — including the Rasuwagadhi border bridge — markets and riverside communities were destroyed or damaged along the same stretch.

The response

Nepal mobilised the Nepal Army, the Armed Police Force and Nepal Police, with helicopters and medical teams, to reach cut-off villages along the Bhote Koshi and Trishuli. The National Disaster Risk Reduction and Management Authority (NDRRMA) convened emergency coordination, and the Nepal Red Cross activated emergency response teams and deployed relief.

The disaster's cross-border reach drew an international response. South Korea set up a task force over its missing citizens. In China, President Xi Jinping called for continued efforts to locate the missing and for improved disaster monitoring and early-warning systems.

A cause still in dispute

Crucially, authorities have not yet established a cause for the floods, and experts have put forward three competing explanations. Nepal's Foreign Minister Shishir Khanal said an earthquake triggered an avalanche or landslide that blocked the Bhote Koshi; the US Geological Survey recorded a magnitude 4.4 earthquake in Tibet, and roughly seven minutes separated that quake from a border security-camera timestamp of the surge. The International Centre for Integrated Mountain Development (ICIMOD) offered two glacier-related explanations instead — a rock-ice avalanche off a glacier on the Nepal side that dammed and then released the Lhende Khola, and, from satellite analysis, the sudden drainage of a supraglacial lake north of Nepal's Langtang Himal. We examine the evidence for each in a separate report: what really caused the Bhote Koshi flood — earthquake, avalanche or a bursting glacial lake.

What this means if you are travelling in Nepal

For trekkers, the geography matters. Syabrubesi is the road-head where essentially every Langtang Valley trek begins, reached along the Pasang Lhamu Highway from Kathmandu, and Timure sits on the Rasuwagadhi border road. In other words, the flood struck the gateway to Langtang and the Kathmandu–Kerung overland route to Tibet, with the overland Mt Kailash route via Kerung reported closed.

The damage reported so far is in the Bhote Koshi and Lhende corridor around Syabrubesi and Timure and downstream — the condition of the trail up the Langtang valley itself has not been established and is being assessed. This is late monsoon; Langtang's main trekking season is October–November, still several weeks off, which is relevant for repair and recovery, though road and bridge access via Syabrubesi may be disrupted in the meantime. If you have a trip planned in the region, check directly with your operator and the authorities before travelling. Our companion guide sets out the practical picture: Rasuwa flood and your Langtang trek — what to check before you go.

This is also not the first time this river has flooded. The Bhote Koshi and Lhende flooded in July 2025 as well — an event attributed to the drainage of a supraglacial lake in Tibet — meaning this stretch has now flooded twice in around 14 months. ICIMOD's Saswata Sanyal has said such events are increasing at an "unprecedented" pace in the Hindu Kush Himalaya, a pattern we cover in our reporting on climate change in the Himalaya.

Cover photo: Anil Simkhada via Wikimedia Commons (CC BY-SA 3.0).