Nepal Bhotekoshi-Trishuli Flood: A Timeline of the Disaster and What Is Known So Far

A timeline of the Bhotekoshi–Trishuli disaster, compiled from public reporting and official statements. Last updated 29 August 2026. Casualty figures are provisional and still changing — see the note on numbers at the end.

On the morning of Wednesday, 26 August 2026, a mass of rock and glacier ice broke away high in the Himalaya near the Nepal–China border and fell into the headwaters of the Lhende Khola. Within hours the resulting debris flow had travelled roughly 100 kilometres down the Bhotekoshi and Trishuli rivers, destroyed the Rasuwagadhi–Gyirong border crossing, wrecked a string of hydropower projects and swept through settlements in eight districts. It is the deadliest single disaster to strike Nepal in years.

This article sets out what happened, hour by hour, and what remains unknown.

The trigger

Scientists are clear on one point: this was not an earthquake. The seismic signal recorded that morning was generated by the collapse itself.

8:20 AM NPT — A small tremor, magnitude 2.6, is recorded near the Rasuwagadhi border area.
8:37 AM NPT — A far larger signal, magnitude 5.2, is recorded and initially misreported as a magnitude 4.4 earthquake. It is in fact the slope failure: a mass roughly 610 metres wide falling some 1,200 metres near Langtang Lirung, inside Langtang National Park.
~11:40 AM NPT — A second failure, magnitude 4.2, is detected about three hours after the first.

The US Geological Survey notes that researchers have not yet settled whether the initial failure was "a landslide incorporating part of a glacier or a glacial collapse." Either way, the ice and water in the moving mass melted rapidly, and the flow gathered more debris and water as it funnelled into existing stream channels.

The avalanche appears to have dammed the Lhende Khola about 20 kilometres upstream of the Miteri Bridge, forming a temporary debris-dammed lake. When that dam failed, it released the surge downstream.

26 August: the surge

The flood moved faster than any warning system could keep up with. Over its first stretch it averaged roughly 180 km/h.

Time (NPT)	Event
8:40 AM	Syabrubesi station records the Bhotekoshi at 1.62 m — warning level is 6 m, danger level 9 m
8:44 AM	CCTV captures the surge destroying Gyirong Port, ~20 km covered in about 7 minutes
8:50 AM	Syabrubesi station stops transmitting; the surge hits the Rasuwagadhi customs complex and friendship bridge, sweeping away three Nepal Police facilities
9:00–9:05 AM	The Flood Forecasting Division learns a major flood has entered the Bhotekoshi from Tibet; the surge enters the Trishuli
9:15–9:16 AM	Emergency SMS alerts go out to 679,295 residents of Rasuwa, Nuwakot, Dhading and Chitwan
9:20 AM	Betrawati station stops transmitting; last reading 3.55 m
11:26 AM	Phurke station records the Trishuli above its danger mark
11:43 AM	The Phurke river bridge and Malekhu station are swept away
1:00 PM	The flood is confirmed past Muglin; residents from the Trishuli down to Devghat are alerted
1:35 PM	Warning issued that the lake formed by the blockage in China has not fully drained
2:14 PM	Kalikhola station passes danger level, peaking at 12.3 m
4:00 PM	Devghat peaks at 6.57 m and begins to fall
6:13 PM	The International Charter on Space and Major Disasters is activated, with UNITAR as managing agency
6:30 PM	Devghat falls to about 4 m. An estimated 20 million m³ of additional water has passed. Four automatic hydrological stations have been destroyed

By that evening, Prime Minister Balendra Shah had deployed the Nepali Army, Armed Police Force and Nepal Police, with 14 helicopters mobilised. The Department of Roads confirmed that the 42-kilometre road linking Betrawati to the Rasuwagadhi border was destroyed at multiple points, with a further 16-kilometre section swept away. The Nepal Electricity Authority reported damage to 14 hydropower projects totalling 748 MW of capacity, plus a 220 kV substation — taking around 430 MW off the national grid.

Nine commercial bank branches were swept away with 26 staff unaccounted for. The Rasuwa customs office lost contact with 15 employees.

27 August: the scale becomes clear

Nepal Police put the confirmed death toll at 165, with 73 injured and 826 people missing — 579 of them travellers, including 466 foreign nationals. China reported three dead and 558 missing near Gyirong Port.

Later the same day, Nepal's Ministry of Foreign Affairs reported 359 bodies recovered and 596 people from 33 countries missing, cautioning that the figures were "subject to verification as search and rescue operations continue." The largest groups of missing foreign nationals were from India (167), China (100), the United States (66), Ukraine (53) and Malaysia (51).

The government declared the affected area a disaster zone for three months. The Ministry of Finance redirected roughly Rs 20 billion from the current fiscal year's budget. Prime Minister Shah travelled to Nuwakot to monitor the response; he and his cabinet pledged a month's salary to the Prime Minister's Natural Disaster Relief Fund.

Chinese authorities warned that a barrier lake of about 2 million m³ had formed at the confluence of the Chhochen Khola and Purepu Tsangpo, with a high risk of breaching.

The IFRC launched a 24-month emergency appeal for CHF 25 million. UNICEF reported at least 17,000 children in urgent need, with 18 schools destroyed and 20 damaged.

28 August: the breach scare, and the tunnels

Rescue work was halted for about three hours when the Rasuwa Chief District Officer reported the barrier lake had breached or was overflowing, and police urged crews to move to higher ground. Officials later confirmed the water level had risen only about 0.6 m and the immediate risk had eased. A Chinese engineering team of eight was deployed; the lake level subsequently fell by around 10 metres.

Nepal's toll rose to 579 dead, with more than 1,900 missing — a jump driven largely by the addition of 933 hydropower workers to the missing list. Around 14,829 security personnel were mobilised. The IFRC estimated at least 93,000 people affected.

In India, four badly decomposed bodies were recovered from rivers in Uttar Pradesh's Maharajganj district, carried roughly 240 kilometres downstream. India later reported seven.

Nepal's Foreign Ministry stated that no foreign search-and-rescue teams were required, while accepting material assistance.

29 August: where things stand

The National Disaster Risk Reduction and Management Authority reported between 616 and 626 confirmed deaths, with bodies recovered across eight districts:

District	Bodies recovered
Chitwan	233
Nawalparasi East	158
Nuwakot	51
Gorkha	48
Nawalparasi West	47
Dhading	45
Tanahu	31
Rasuwa	13

The missing figure in Nepal stood at 1,924, including 517 foreign nationals. Tibet reported 7 dead and 554 missing, having evacuated 555 stranded tourists and 499 residents. Roughly 2,500 people had been brought out by rescue teams.

The hydropower workers

This is now the centre of the rescue effort, and the most uncertain part of the picture. The Independent Power Producers' Association of Nepal reports 934 people linked to 11 hydropower projects unaccounted for; NEA officials have cited over 200 workers still missing. Hundreds are believed trapped in tunnels and underground powerhouses along the Trishuli corridor, with tunnel entrances buried, access roads gone, and — in some cases — no confirmed location for the workers at all.

Project	Status
Upper Trishuli-1 (216 MW)	254 rescued, operations ongoing
Upper Trishuli-3 (37 MW)	213 initially missing, 85 rescued
Upper Trishuli-3A (60 MW)	~350 rescued; 100+ still trapped in tunnel
Upper Trishuli-3B	20–25 unaccounted for
Langtang Khola (20 MW)	18 rescued, 42 unaccounted for
Rasuwagadhi	49 employees missing
Chilime (22.1 MW)	8 out of contact, 6 believed trapped in a mud-filled tunnel

The Nepali Army has prioritised 19 tunnels, under Brigadier General Manoj Thapa. Rescuers face mud-filled tunnels, damaged powerhouses and concerns about oxygen in underground sections. On 29 August, operations were temporarily suspended at points because of rain and fog — "Search and rescue operations have been temporarily halted because it is raining and the weather is foggy," said Narendra Pariyar, the senior bureaucrat for Rasuwa district.

Damage

Preliminary official estimates put total damage in Nepal at around Rs 200 billion (roughly US$1.3 billion), with about Rs 15 billion of that in roads and bridges alone. Forty-one bridges were damaged. The Gyirong Port complex on the Chinese side was destroyed outright; the Rasuwagadhi customs yard lost more than 300 vehicles. Municipal offices in Gosaikunda and Uttargaya were washed away. More than 1.5 metres of silt was deposited across the main disaster zone.

The warning that didn't come

The existing flash-flood early warning system was built for monsoon flooding — gradual rises detected by water-level monitors — and could not detect this event in time. The upstream monitoring stations were swept away before alerts could be issued. The area has been described as a monitoring blind spot that had received little attention from geologists. The first SMS alerts reached residents at 9:15 AM, roughly 38 minutes after the collapse and around 25 minutes after the surge had already destroyed the border post.

International response

Aid pledged or delivered includes: the UN Central Emergency Response Fund (US$2 million) and WHO emergency medical supplies; the European Union (€2 million, plus activation of the Copernicus satellite system); the Asian Development Bank (US$5 million grant); the World Bank (indicating up to Rs 25 billion could be mobilised); the United Kingdom (£5 million); Canada (CA$5 million and five consular officials); South Korea (US$1 million, with Doosan Group pledging a further US$5 million); Sri Lanka (US$1 million); the United States (US$500,000 and a disaster response advisor); India (62.5 tonnes of relief supplies by 29 August); Bangladesh (over Rs 200 million in tents, food and body bags); and Pakistan and Malaysia (emergency and rescue teams). Médecins Sans Frontières deployed an emergency team. India, China, Australia and South Korea have been permitted to contribute DNA testing and forensic expertise, and Nepal has requested heavy-lift cargo drones from international partners.

A note on the numbers

The figures in this article disagree with one another, and that is not an error in the reporting — it reflects the situation. Different bodies are counting different things at different moments: NDRRMA, Nepal Police, the Ministry of Foreign Affairs, the IFRC and Chinese authorities have each released figures on their own schedule and with their own verification thresholds. The missing count in particular jumped sharply on 28 August when 933 hydropower workers were added at once. Some international outlets have reported combined missing totals approaching 2,500–3,000 by aggregating Nepali and Chinese figures.

Treat every number here as provisional and attributed to the moment it was given. They will change.

What is still unknown

The true toll. With 1,924 people missing in Nepal alone and bodies recovered as far as 240 km downstream in India, the confirmed death toll is expected to rise substantially.
The fate of the tunnel workers. Hundreds remain unaccounted for underground, and rescuers do not have confirmed locations for all of them.
The exact mechanism. Whether this began as a landslide that incorporated glacier ice, or as a glacial collapse, is unresolved.
Further lake outburst risk. Authorities have been monitoring more than one impounded body of water in the upper catchment, with concern about a cascading release.
Accountability for the warning gap. Whether the monitoring network can be redesigned for sudden, non-monsoon events of this kind is now an open policy question.