Nepal Flash Flood Kills at Least 18 as Hundreds Remain Unaccounted for Near Tibet Border

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At least 18 people have been killed and nearly 400 remain unaccounted for after a powerful flash flood and mudslide swept through communities near Nepal's border with Tibet, destroying buildings, bridges and roads and disrupting communications and electricity.

The disaster struck early Wednesday in Rasuwa, a mountainous district north of Kathmandu, along the Bhote Koshi River, which flows from Tibet into Nepal. Search and rescue operations are under way on both sides of the border, with the Nepal Army saying 88 people have been rescued so far.

The number of people still missing includes 291 tourists and 93 Nepali nationals who were known to be in the affected area. The tourists include people from the United Kingdom, United States, India, Malaysia and South Africa. Nepalese officials have warned that the eventual loss of life could be significantly higher as rescue teams struggle to reach isolated areas.

One earlier assessment put the death toll at eight, reflecting the rapidly changing situation as authorities began assessing the disaster. Later information reported by the BBC put the toll at 18.

A sudden flood with little warning

The scale of the flooding appears to have left many people with little time to escape. Authorities said roads and communications were cut, while strong winds and difficult terrain hampered helicopter operations.

Verified video from Nepal shows floodwaters rapidly swelling the Trishuli River, carrying large amounts of sediment. A bridge is seen being ripped from its supports and swept downstream, followed shortly by the collapse of several buildings.

In another video from the same area, much of the landscape along the riverbank appears devastated, with buildings destroyed, partially collapsed or covered in sediment.

A businessman in Kathmandu told the BBC that his logistics company had lost contact with seven container trucks and their Nepalese employees in the affected area because there was no functioning signal.

Nepalese authorities have also reported missing security personnel. Foreign Affairs Minister Shishir Khanal said 26 police officers, nine armed police officers and 44 military personnel were among those missing.

Possible earthquake and avalanche trigger

The exact chain of events is still based on preliminary information. Nepal's foreign affairs minister said an earthquake recorded at 08:37 local time may have triggered an avalanche, sending melted snow and water into the Bhote Koshi River and producing the flash flood.

A separate assessment cited by Al Jazeera pointed to an ice-rock avalanche from a glacier as the likely trigger. Experts from the International Centre for Integrated Mountain Development said the Lhende Khola, a tributary of the Bhote Koshi, experienced extreme flooding after the event.

Because the cause remains preliminary, authorities have not established a definitive explanation for the disaster.

The flooding has also affected infrastructure downstream. Nepal's authorities reported damage to the Trishuli hydropower project, while roads, communications and electricity supplies have been disrupted. The main road toward Kathmandu has been closed, cutting off some communities.

Across the border in Tibet, Chinese state media reported major casualties and people missing after a mudslide struck the Gyirong area. Roads, communications and power were also reported to have been damaged, although the full extent of the destruction there remains unclear.

Rescue teams face difficult conditions

The Nepal Army has deployed helicopters and disaster-response personnel, but access remains difficult. Officials said aircraft have struggled to reach some locations because of high water, strong winds and damaged roads.

Rescue teams are particularly focused on areas including Timure, Syabrubesi and Betrawati, where Nepal's Ministry of Home Affairs warned of potentially extensive loss of life. Authorities have urged people living near riverbanks and other vulnerable areas to move to safer locations and remain alert.

Prime Minister Balendra Shah held an emergency meeting with the country's disaster management authorities and said rescue and relief work had begun in coordination with medical teams, scouts and the Red Cross.

The disaster comes after deadly flooding in the same broader region last year. That event killed 18 people and followed a glacier-related flood on the Chinese side of the border. Nepalese officials told the BBC they believe Wednesday's disaster is even larger.

For now, the priority remains locating those still missing and reaching communities cut off by the flood. The final death toll and the full extent of the destruction are not yet known, particularly in the mountainous areas on both sides of the Nepal-Tibet border.