Flash floods at the Nepal-Tibet border are expected to cause major casualties.

Torrential floods in China’s Tibet and Nepal’s Himalayan border regions have left hundreds missing and at least 22 dead. In Nepal, houses, roads, bridges, and power projects were destroyed; in Tibet, officials reported that they feared “major casualties,” with some people missing in the county of Gyirong after a mudslide struck a border crossing between the neighbors.

384 visitors, including 291 from the United States, Malaysia, India, and the United Kingdom, were reported missing, according to officials. Because the river was flowing above its normal course, rescue helicopters were unable to land in the impacted regions of Syapru Besi and Timure in the hilly district of Rasuwa, Nepal, which is home to roughly 50,000 people, according to officials.

Witnesses told that entire villages were submerged in the floodwaters, while television showed footage of crumbling houses, floating automobiles, and a metal bridge being washed away.

Following reports of communities and project sites being swept up, district administrator Narendra Pariyar warned residents on the banks of the Bhote Koshi River to relocate to higher land because “there could be heavy casualties or loss of property.”

“There is devastation everywhere we look,” Tula Bahadur BK, a health worker in Rasuwa, told. “The settlements next to the river have been completely swept away. Five of my own relatives are missing.”According to army spokesperson Raja Ram Basnet, Nepal’s rescue helicopters won’t be able to land in the impacted districts until the waters recede.

Although the reason of the flooding was initially unclear, the draining of a glacial lake was subsequently identified as the source of a fatal flash flood that occurred on the same river last year.

Although it did not provide further details, China’s official Xinhua news agency stated that the mudslide happened on the Nepali side and struck the Gyirong port, cutting out power, roads, and communications in the Shigatse area close to the Nepali border. In order to prevent subsequent tragedies, Xi Jinping, the president of China, called for “all-out” search operations for the missing as well as improved monitoring and early warning systems.

According to an assessment by Nepal’s energy ministry, 430MW of electricity supplies—mostly from hydroelectric projects—were impacted. This represents more than 12% of the country’s 3.2GW hydropower potential.

Nepal’s prime minister, Balendra Shah, stated that the military and police were joining the rescue attempt. He stated, “Instructions have been given… to move the people living in the lower areas to safer places.” “Those who live near the river are urged to use extra caution and stay vigilant.” The Bhote Koshi River originates in Tibet and empties into the Trishuli River in Nepal, which then flows into India as the Gandak River.

Nine people were murdered in last year’s Bhote Koshi flood, which destroyed a “friendship bridge” that connected China and Nepal and caused months of disruption to trade and transportation. According to a regional climate monitor, the emptying of a supraglacial lake in Tibet caused that deluge.