At least 18 people have been killed and nearly 400 others are unaccounted for after a flash flood and mudslide along the Nepal-Tibet border swept away villages and damaged roads and infrastructure, according to the BBC.
The flood hit early on Wednesday in Rasuwa, just north of Nepal's capital Kathmandu, with preliminary information suggesting it was caused by an earthquake triggering an avalanche, sending melted snow pouring into the Bhote Koshi river.
Search operations are under way on both sides of the border, and 88 people have been rescued so far, according to the Nepalese army. State media in China, which controls Tibet, say there are significant casualties, and Nepalese officials said they anticipate a "huge scale loss."
The Nepal tourism board said work was underway to establish the whereabouts of 291 tourists and 93 Nepalese nationals, including guides, who were known to be in the area where the flood hit. They include 12 travelers from the U.K. as well as Americans, Malaysians, South Africans and Indians.
Several areas downstream of the Bhote Koshi river, which flows from Tibet to Nepal, are on high alert, and roads, communications and power in the region have been disrupted. Authorities say the main road to Kathmandu is closed.
Verified videos from Nepal show a bridge being swept away and multi-story buildings collapsing by the force of floodwaters in the town of Trishuli Bazaar, in Nuwakot District, about 25 kilometers (16 miles) northwest of Kathmandu.
The footage shows the Trishuli River suddenly swelling with sediment-filled water before the flash flood rips the bridge off its supports, followed seconds later by the collapse of several buildings.
Yee Liang, a Chinese businessman based in Kathmandu, said he lost contact with seven employees stationed in the area. "There is no signal, so we cannot reach anyone," he said, adding that there had been no warning before the flood struck.
Nepal army spokesman Rajarm Basnet said efforts were underway to rescue 115 people from the village of Mailung. The Nepalese Ministry of Home Affairs warned of likely heavy loss of life in Timure, Syabrubesi and Betrawati, and said the flooding had also damaged the Trishuli hydropower project.
The extent of the damage on the Tibetan side remains unclear. Nepal's Foreign Affairs Minister Shishir Khanal told parliament that 26 police personnel, nine armed police officers and 44 members of the military were missing. He said an earthquake at 8:37 a.m. local time (2:52 a.m. GMT) had triggered an avalanche believed to have caused the flash flood.
Prime Minister Balendra Shah said an emergency response was under way in coordination with medical teams, scouts and the Red Cross.
Rasuwa saw deadly flooding last year that killed 18 people after a glacier burst on the Chinese side of the border. Officials believe Wednesday's disaster exceeds the scale of last year's floods.