Glacier collapse triggers catastrophic Nepal-Tibet border floods; 600+ dead, thousands missing

A glacier collapse on the Nepal-Tibet border on Wednesday unleashed catastrophic flooding and landslides that killed at least 579 people in Nepal and 5 in Tibet, with approximately 2,000 people unaccounted for, according to Nepal's National Disaster Risk Reduction and Management Authority and Chinese state reports.

Initial reports attributed the disaster to an earthquake, but the U.S. Geological Survey later confirmed the cause was a glacial collapse, in which a glacier or part of a glacier disintegrated. The impact of the collapsed glacier hitting the valley floor registered a magnitude 5.2 and sent a wall of mud and debris traveling 62 miles downstream along the Trishuli and Bhote Koshi Rivers, sweeping through towns popular with mountaineering tourists and pilgrims in northern Nepal.

Footage showed the flood destroying buildings, roads, and vehicles in the Nuwakot region. A towering wall of water and mud enveloped the Rasuwagadhi Border checkpoint, a multi-storey building on the Nepalese side. Across the border in Tibet, Gyirong Port was also struck, with deaths reported in Tibetan villages.

Oxford University Earth Sciences professor Mike Searle told the BBC the glacier could have collapsed "hours or days" before the flooding. "I think the sheer wave of debris suggests there was a landslide first, the water built up, dammed the river, and then it burst in one huge great flood," he said. The International Centre for Integrated Mountain Development has warned that secondary flooding could occur in coming days from debris in river systems.

The barrier lake risk presents an escalating threat. As of Friday, an estimated 2.5 million cubic meters of water had accumulated in a lake that formed after the landslide at the confluence of the Chhochen Khola and Purepu Tsangpo rivers, according to Chinese state broadcaster CCTV. China has warned there is a "high risk" the lake may burst its banks, causing fresh flooding downstream. State media reported rescue operations were briefly suspended on Friday after the lake overflowed, though water levels later dropped slightly. Experts told the BBC it was possible the lake could drain naturally over time.

The missing include 517 foreign nationals across dozens of countries, according to the government, with at least 33 British nationals among them. India's foreign ministry says at least 320 Indian nationals are missing. The Chinese foreign ministry reports nearly 100 Chinese nationals missing in Nepal. The U.S. State Department says 90 Americans are unaccounted for, Ukraine reports 62 nationals missing, Australia 39, Malaysia 51, Canada 30, and smaller numbers from South Korea, South Africa, Portugal, the Netherlands, and New Zealand. Nepal's police also reported 44 army members and 28 police officers among the missing.

Chinese state media reported 5 deaths and 558 missing in Tibet, figures the BBC notes have not been independently verified. Tibet is one of China's most strictly controlled regions, and foreign media access is virtually impossible. The BBC also cautioned that it remains unclear whether any missing persons have been counted in both Nepali and Chinese figures. Beijing has launched a massive rescue operation with hundreds of emergency workers continuing operations. President Xi Jinping chaired an emergency meeting to coordinate efforts, and Premier Li Qiang visited the region to inspect debris removal, a rare deployment of China's second-most important leader so soon after a major disaster. The International Campaign for Tibet praised first responders but said Beijing had been removing videos and firsthand information from social media, calling on Chinese authorities to "disclose complete and verifiable information about the damage and casualties."