A flash flood and debris avalanche struck the Nepal-China border region on the morning of Wednesday, 26 August 2026. The disaster was triggered by a rapid slope failure associated with a glacier collapse on Langtang Lirung in Langtang National Park.

Seismic instruments detected movement in the mountains above the border at 8:37am local time on 26 August 2026. The impact of the collapsed glacier generated energy equivalent to a 5.2 magnitude earthquake. CCTV footage from Gyirong shows the flood arriving at 10:59:53 local time on 26 August 2026. The resulting torrent of water, ice, and debris traveled nearly 100 km downstream through the Lende Kholā and Trishuli River valleys.

Chinese authorities reported 16 deaths in Tibet related to the flooding. Chinese authorities reported 546 people missing in Tibet as of Sunday. At least 275 Indians remain missing in Nepal, according to India's foreign ministry.

At least eight people are believed missing at the Chilime hydropower plant in Rasuwa. An Indian team is working alongside the Nepali army using pumps and excavators to locate missing people at the Chilime hydropower plant. Rescue teams are currently attempting to free around 100 hydropower workers believed trapped in multiple tunnels.

The floods knocked out about 10% of Nepal’s power capacity. The damage to hydropower infrastructure is estimated to have taken 700 megawatts out of service. Hydropower projects in Rasuwa, Nuwakot, and Dhading districts were fully or partly destroyed.

More than 40 bridges were destroyed by the flooding. Tens of kilometers of roads, multiple bridges, schools, and hospitals were destroyed. The Friendship Bridge linking Nepal and China was swept away. Nepal’s immigration and customs facilities at Rasuwagadhi were swept away.

The Red Cross estimates that more than 93,000 people have been affected by the disaster. Almost 21,000 security personnel are involved in rescue operations alongside civilian workers and volunteers. China mobilized more than 2,100 rescue workers and allocated at least 220m yuan to support relief efforts.

India and China are sending prefabricated truss bridges to help restore access. Nepal has said it does not need foreign help in general search and rescue operations but has leaned on India and China for expertise in tunnel rescues.

Rescue operations have been suspended several times since Friday due to bad weather and concerns that a lake formed across the border could trigger fresh flooding. The International Charter Space and Major Disasters and the Copernicus Emergency Mapping Service were activated to provide satellite imagery for emergency response.

Electronic records show that 89 Nepali and foreign nationals had cleared immigration to leave Nepal for Tibet before the flood. The Nepal immigration system recorded its final transaction at 8:35:03am local time on 26 August 2026. Four immigration employees, including the head of the Rasuwagadhi office, went missing in the floods.

The body of the head of the Rasuwagadhi immigration office was recovered far downstream. The female official who recorded the final immigration transactions is still missing. Tika Ram Pokharel, a senior immigration assistant at Rasuwagadhi, was the only member of his office known to have survived.

Among the foreign nationals recorded leaving Nepal that morning were 32 Indians, 12 Chinese nationals, and nine Americans. Citizens of Britain, Canada, Australia, and Italy were among the foreign nationals recorded leaving Nepal before the flood. Around 300 to 400 people were waiting to leave Nepal for Tibet on the morning of the flood, according to Tika Ram Pokharel. Hundreds of bodies swept down the mountains by the torrent have been buried in shallow graves after DNA testing.

Disaster epidemiologist Jennifer Horney said the first 72 hours are critical for survival as chances drop without access to clean water. Geoscientist Jakob Steiner said access to breathable air is a key factor for survival in the trapped tunnels. It is unclear whether emergency supplies were stocked in the tunnels where workers are trapped.

The tunnels are large enough for trucks to drive through. In a 2023 Himalayan tunnel collapse caused by a landslide, 41 Indian workers were rescued after being trapped for 17 days. The 41 Indian workers trapped in the 2023 tunnel collapse were provided food, water, and oxygen through pipes.

Horney said there just really wouldn’t be a way to go much further than three days without safe, drinkable water. Steiner said the tunnels are big enough to drive trucks through. He said from what they understand, they have managed to get oxygen to some of those stuck inside and are trying to rescue them now. He added that it is a race for time, though, as people need food and water.

Two Nepali officials said China had not shared much information on glacier risks and water levels after a meeting earlier this year. China’s foreign ministry said Beijing had continuously provided Nepal with meteorological and hydrological data. Glaciers across the Hindu Kush Himalaya are losing ice at an accelerating rate, according to reports by the International Center for Integrated Mountain Development.

The Coalition for Disaster Resilient Infrastructure estimates that $124 billion worth of Nepal’s infrastructure is exposed to climate-driven disasters. A report by the Coalition for Disaster Resilient Infrastructure found that Nepal’s average annual losses from various disasters are nearly $760 million. Steiner said authorities have to take a hard look in the mirror now and ask how they will be rebuilding in these places.

He said they will also have to take a close look at other projects in Nepal that have not been built yet, whether they’ll be approved after this event. Ramraj Narasimhan, a senior director, said if it gets damaged, let it get damaged, but asked whether redundancy can be built into the system. Coordinator Himanshu Thakkar said environmental, social and disaster-risk assessments need to reflect the specific landscape and past hazards of each valley, backed by land-use rules and stronger accountability. Prime Minister Balendra Shah said despite the adverse weather, difficult terrain and continuing risks, they are moving forward with determination to save the lives of their citizens.

Why It Matters

The disaster shows the vulnerability of Nepal's hydropower infrastructure, which accounts for a portion of the nation's energy supply. The loss of 700 megawatts represents about 10% of the country's total power capacity, affecting millions of residents and industries. The scale of the destruction, including the loss of critical border infrastructure like the Friendship Bridge, disrupts trade and travel between Nepal and China.

The event reflects the growing risks posed by climate change in the Himalayan region, where glaciers are retreating at an accelerating rate. With $124 billion worth of infrastructure exposed to climate-driven disasters and average annual losses nearing $760 million, the financial and human costs of such events are substantial. The differing accounts regarding data sharing between Nepal and China point to potential gaps in regional cooperation on disaster preparedness and risk management.

Timeline

In 2023, in a Himalayan tunnel collapse caused by a landslide, 41 Indian workers were rescued after being trapped for 17 days. On Wednesday, 26 August 2026, a flash flood and debris avalanche struck the Nepal-China border region.

A glacier collapse on Langtang Lirung triggered the event, which killed 903 people in Nepal and left hundreds of hydropower workers trapped in tunnels. Rescue teams are working to reach more than 900 missing hydropower workers, hundreds of whom are feared trapped in the tunnels of 11 hydropower projects.

What's New

A glacier collapse on Langtang Lirung triggered the disaster, which killed 903 people in Nepal and left hundreds of hydropower workers trapped in tunnels. Background context includes a study titled "Refined energy-balance modelling of a supraglacial pond, Langtang Khola, Nepal" published in 2015 in Annals of Glaciology. Another study titled "Dark Tourism: A Preliminary Study of Barpak and Langtang as Seismic Memorial Sites of Nepal" was published in 2019 in Journal of Tourism and Hospitality Education.

How Sources Differ

Sources differ on the number of hydropower workers trapped. There is also a detail gap regarding the missing hydropower workers. The Independent Power Producers’ Association Nepal statement says that hundreds of workers are unaccounted for from a dozen hydropower projects.