KATHMANDU — A sudden collapse of a wall of mud and rock on the Himalayan border between Nepal and China’s Tibet on Aug. 26 unleashed catastrophic flooding that has killed at least 95 people and left hundreds unaccounted for, officials said, as rescue teams raced to reach isolated communities.
Verified footage from the border region shows a surge of mud, ice and water sweeping away villagers, buildings and vehicles. Authorities on both sides of the frontier warned that casualties could rise sharply. In Nepal, entire settlements, roads and a metal bridge were destroyed in the mountainous Rasuwa district; Chinese state media reported damage and blocked access at the Gyirong land crossing in Shigatse region.
Nepal’s Foreign Minister, Shisir Khanal, told parliament that an earthquake may have triggered an avalanche that led to the flood. The German Research Centre for Geosciences recorded a magnitude-4.4 quake about seven minutes before security-camera footage captured the collapse. Specialists said an ice-rock avalanche in the Lhende Khola river likely triggered the sudden surge, though the precise cause remains unconfirmed.
Nepal’s tourism authority reported at least 340 travellers missing, including 105 Indians, 93 Nepalis, three U.S. citizens and 12 British nationals; Malaysia’s foreign ministry said 11 Malaysians had lost contact with their agencies. South Korea reported eight workers at a hydropower site missing and 10 stranded; the workers were employed by Korea Energy and Doosan Enerbility. Nepal has deployed rescue teams and helicopters, though aircraft could not land in the hardest-hit valleys.
Authorities warned of a possible second flood after debris lodged upstream on the Nepal–China border. With rivers swollen, flood alerts were issued downstream in India’s Uttar Pradesh and Bihar, where melt and runoff from the Himalayas feed lowland waterways.
China’s state media said at least 574 rescuers had been dispatched to Gyirong, but access was hindered by up to 1.5 metres of sediment that surged from the Nepalese side. Chinese President Xi Jinping called for “all-out” search efforts and urged strengthened monitoring and early-warning systems to prevent further disasters.
Nepal’s energy ministry said the disaster disrupted about 430 megawatts of hydropower output, more than 12% of the country’s installed hydropower capacity, compounding the emergency by affecting electricity supplies. Nepal’s prime minister, Balendra Shah, said police and military forces were assisting rescue operations and ordered residents in low-lying areas to move to higher ground.
Indian Prime Minister Narendra Modi offered New Delhi’s full humanitarian assistance as coordination between the neighbouring countries intensified. The Bhote Koshi river, which flows from Tibet into Nepal and onward into India as the Gandak system, has produced destructive flash floods in recent years; a 2025 flood caused by a drained supraglacial lake killed nine people and disrupted cross-border infrastructure.
With communications and roads cut in parts of Rasuwa and Gyirong, officials warned that search-and-rescue operations would be prolonged and hazardous. Local health workers described widespread devastation and appealed for urgent support as authorities try to account for the missing and secure vulnerable communities.