The disaster has caused widespread destruction on both sides of the border, with homes, roads, bridges and electricity infrastructure damaged or swept away by powerful floodwaters and massive flows of mud and rocks.
Footage from the affected areas showed people being swept away by landslides containing mud and boulders, as authorities in Nepal and Tibet expressed concern over the growing number of casualties.
In Nepal, the disaster severely affected communities close to the border with Tibet. Authorities said a large number of people were killed, while rescue teams continued searching for those who remain trapped or missing.
Officials in Tibet also reported multiple deaths and disappearances in the Gyirong area after a major landslide struck a border crossing.
One survivor, 68-year-old Keshav Prasad Baral, said he saw what appeared to be a massive wall of mud rushing toward his home.
He said he tried to grab his wife’s hand and pull her out of the house to safety, but she was swept away by the mudslide. Baral was rescued by helicopter four or five hours later, but his wife remained missing beneath the debris.
Reports indicated that an earthquake in the area may have contributed to the landslides and subsequent flooding.
Nepal’s Prime Minister’s Office said 484 tourists were missing, including 391 foreign nationals and 93 Nepali citizens.
A tourism official said those missing included 133 Indian nationals who were travelling to Mount Kailash in Tibet, a site considered sacred by Hindus. The missing also included 47 Americans, 34 Australians, 33 British nationals and 24 Canadians.
Researchers believe a massive landslide involving rocks and ice may have blocked the flow of rivers, causing a sudden release of water, mud and debris that swept through communities downstream.
Rescue operations have been complicated by the mountainous terrain and severe weather conditions. Helicopters have struggled to reach some of the affected areas in Nepal because of heavy rainfall and difficult access.
Television footage showed destroyed homes, vehicles swept away by floodwaters and a steel bridge being washed away.
China’s state news agency Xinhua reported that landslides had also struck the Gyirong Port area, damaging roads, communication networks and electricity infrastructure in Shigatse, near the Nepal border.
The Chinese military deployed drones to assess the scale of the destruction and prepared helicopters and other emergency equipment to support rescue operations.
Chinese President Xi Jinping called for an expanded search for missing people and stronger early-warning systems to help prevent further disasters.
The mud-filled floodwaters reportedly descended from an area nearly 2,000 metres above sea level, prompting flood alerts in parts of northern India bordering Nepal.
Authorities in India’s Bihar state said around 5,000 people had already been evacuated from six affected areas, while plans were being made to relocate between 10,000 and 12,000 people from vulnerable communities.
The Bhote Koshi River originates in Tibet and flows through Nepal, where it joins the Trishuli River before continuing towards India as part of the Gandak River system.
The region has experienced deadly flooding before. Last year, floods along the same river killed nine people and left 24 others missing. The disaster also destroyed the Friendship Bridge connecting Nepal and China, disrupting transport and cross-border trade.
