A catastrophic flash flood triggered by a glacial collapse along the Nepal-China border has killed more than 160 people and left hundreds of others missing, including hundreds of foreign tourists and pilgrims, as rescue teams continue a desperate search across the devastated Himalayan region.

The disaster struck on Wednesday in Nepal’s northern Rasuwa district after a massive surge of water, mud and debris entered the Lhende Khola before flowing into the Bhote Koshi and Trishuli river systems. The torrent swept through settlements, destroyed roads and bridges and damaged hydropower infrastructure.

The flooding also affected China’s Tibet Autonomous Region, where mud and debris hit the Gyirong border area and caused extensive damage to infrastructure.

Nepalese authorities have continued to revise the casualty figures as rescuers reach areas that were initially inaccessible. Latest reports put the number of confirmed deaths at about 165, while hundreds remain unaccounted for.

The National Disaster Risk Reduction and Management Authority said 85 security personnel were among those missing, including 44 Nepal Army personnel, 28 Nepal Police officers and 13 members of the Armed Police Force.

The disaster has also disrupted major transport links. Authorities reported damage to dozens of motorable and suspension bridges as well as approximately 40 kilometres of roads, making access to affected communities extremely difficult.

Nepal Army helicopters have been deployed to evacuate stranded people from isolated communities. At least 123 people, including Nepali and foreign nationals, had been rescued from the Timure area by helicopter, according to Radio Nepal.

The disaster has also triggered an international search for tourists and pilgrims who were travelling through the Himalayan region.

The Nepal Tourism Board said hundreds of tourists were reported out of contact, including hundreds of foreign nationals. Latest figures reported by Nepalese authorities put the number of missing tourists at nearly 600, with Indian nationals forming the largest group among those unaccounted for. Americans, Ukrainians, Australians, Britons, Canadians and citizens of several other countries are also among the missing.

Many of those affected were travelling through routes used by trekkers heading towards the Langtang region and pilgrims travelling towards Mount Kailash and Lake Mansarovar.

Across the border in Tibet, Chinese authorities also reported hundreds of people missing following the mudslide at Gyirong, including more than 250 foreign nationals.

The force of the flood caused widespread destruction along the river valleys, with homes, vehicles, bridges and other structures carried away by the fast-moving water.

The disaster also damaged hydropower facilities, threatening electricity supplies in parts of the country. Roads linking communities to the border were cut off, while damaged communications infrastructure complicated efforts to establish the whereabouts of missing people.

Authorities have warned that the situation remains dangerous as unstable slopes and debris blockages could trigger further flooding and landslides.

Initial reports suggested that an earthquake may have triggered the event, but subsequent analysis indicated that a glacial collapse and associated rock-and-ice debris were responsible for the devastating flood.

The disaster has renewed concerns about the growing risks posed by climate change and rapid glacial melt across the Himalayas. Scientists have warned that warming temperatures can destabilise glaciers and increase the likelihood of sudden glacial lake outburst floods and related disasters.

Nepalese security forces and emergency agencies are continuing operations along the affected river corridors, while authorities on both sides of the border work to locate missing residents, tourists and workers.

The scale of the destruction, damaged road network and continuing risk of landslides are making the rescue operation particularly challenging.

With hundreds still unaccounted for, authorities expect the casualty figures to change as search teams gain access to isolated areas and begin identifying recovered bodies.