King Charles III and Queen Camilla have expressed deep sorrow following the devastating flash floods that have struck the Nepal-China border, leaving at least 353 people dead and an estimated 1,500 missing.

In a written message, King Charles stated, "My wife and I are heartbroken to hear of the devastating flooding that has struck the Nepal-China border." He added, "Many in the United Kingdom have strong, deep and personal ties to this part of the world." The royal couple conveyed their "most profound sympathy to all those who have so tragically lost their loved ones and we feel deeply for the many families awaiting anxiously the news of friends and relations." Special thoughts were also extended to the families of police and armed forces personnel who lost their lives during rescue efforts.

Among the missing are at least 33 British nationals, including a 13-year-old girl and a 14-year-old boy. Horrific footage circulated on social media showing millions of liters of water leveling entire villages, with hundreds of foreign tourists among those unaccounted for.

The United Kingdom has pledged £5 million to aid Nepal in the aftermath of the disaster. Prime Minister Rishi Sunak said the government will "do everything we can" to support British nationals affected by the tragedy and is in contact with relevant authorities.

The flash flood is believed to have been caused by a glacier collapse, which was powerful enough to register as a 5.2 magnitude seismic event on the Richter scale. Chinese government geologist Guo Zhaocheng reported that the ice-avalanche debris flow traveled at approximately 50 meters per second, leaving little time for people to react. The flow extended for over 20 kilometers (12 miles) along the border.

This event involved an ice avalanche that triggered a debris flow, picking up glacial moraine before transforming into a mudslide that impacted port facilities and areas on both sides of the China-Nepal border.

Authorities are warning of a potential second flood risk. A significant landslide dam has formed near the confluence of the Tsogyal River and the Purupqiangzangbu River in Nepal. Chinese Ministry of Water Resources reported that the dam had an estimated water volume of two million cubic meters as of Thursday morning, and the lake was overflowing. An additional three million cubic meters of water is projected to enter the lake within the next three days, raising concerns about the dam's stability and the possibility of another collapse.

Nepal's disaster management authority has also alerted residents and rescue teams along the lower banks of the Bhotekoshi River to the potential for a new flood. Satellite imagery and preliminary analysis indicated that the river had been blocked, forming a lake at the site of Wednesday's flood. Residents and rescuers in areas downstream have been urged to move to higher ground.

In Tibet's Gyirong County, Chinese state broadcaster CCTV reported 558 missing, including 260 foreign nationals. The death toll in China remained at three. The nationalities of the foreign nationals missing in Nepal include 288 from India, 63 from the United States, 51 from Malaysia, 34 from Australia, 33 from Britain, and 25 from Canada. It remains unclear if these figures overlap with those reported by Nepalese authorities.