The toll from massive flooding in the Himalayan mountains of north-central Nepal, along the border with China, rose to nearly 1,500 people on the 26th, two days after the disaster struck.
More than 160 people have died and more than 1,300 remain missing in the floods and landslides in Nepal and China's Tibet, according to Reuters and other foreign news outlets. More than 700 of the missing are foreign nationals. Nepalese authorities, who are conducting search operations, expect the numbers of dead and missing to rise further.
The U.S. Geological Survey, which examined the event, said a large collapse of glacial ice and rock produced signals resembling an earthquake, and that the resulting debris flow caused catastrophic damage. The agency had initially estimated that an earthquake triggered a landslide that led to the flooding, but revised its assessment to melting glacial ice. Hundreds of lakes blocking waterways remain upstream of the affected area, raising the prospect of further flooding.
The disaster began that morning near the Nepal-China border when a huge mass of ice and rock gave way, according to the analysis. The USGS initially reported the observed signals as a magnitude 4.4 earthquake, then raised the magnitude and corrected the cause after further analysis of data from nearby monitoring stations, long-period seismic waves and satellite imagery. "Seismic waves equivalent to magnitude 5.2 were generated, but there was no actual earthquake," the USGS said. "The glacial collapse and debris flow appear to have generated the seismic waves."
Experts point to long-term warming in Nepal as the cause. Decades of warming have accelerated the melting of once-solid Himalayan glaciers, and as soil and gravel mixed in, the refrozen ice failed to harden firmly. The collapsed ice, rock and soil formed earthen walls that acted as a kind of dam in the upper valley, along with a glacial lake, but water swelled in the lake as the glacier melted and the barrier burst.
The ice and rock that broke the barrier poured down the valley and are believed to have unleashed a massive torrent along the existing Bhote Koshi and Trishuli rivers. The torrent of water, mud and rock struck downstream villages, roads, bridges and hydropower facilities, washing away at least 19 bridges and burying several villages in mud and debris. The affected area is a mountain corridor linking Kathmandu and Lhasa in Tibet, as well as a route for Hindu and Buddhist pilgrims heading to Mount Kailash and Lake Manasarovar, leaving many foreign nationals among the casualties. Tourists and pilgrims from more than 20 countries, including India, the United States, Australia, Britain and Canada, are on the missing list.
The International Centre for Integrated Mountain Development, headquartered in Kathmandu, said a snow and rock avalanche originating from a glacier most likely caused the flash flood. "It is believed that a snow and rock avalanche from a glacier on the Nepalese side blocked the Lende Khola, a tributary of the Bhote Koshi, and then suddenly gave way, sending a massive surge of water downstream," ICIMOD said.
The concern is that similar events are likely to recur. In a 2020 survey of potentially dangerous glacial lakes, ICIMOD classified about 47 glacial lakes as hazardous. In the same area, high temperatures caused a glacial lake in Tibet to overflow in August last year, killing nine people and damaging key infrastructure including a bridge connecting Nepal and China.
Koreans are also among the missing. According to the Ministry of Foreign Affairs, nine South Koreans are out of contact — three employees of Korea South-East Power and six of Doosan Enerbility — who had been working at a hydropower construction site in the Rasuwa area. Ten other Koreans who had been stranded with them have evacuated to a safe location. The South Korean government dispatched an 11-member joint rapid response team to the site on the 27th, made up of four officials from the foreign ministry, five from the National Fire Agency and two from the Korean National Police Agency. Working with Nepalese authorities, the team will support the search and rescue of missing people and verify the safety of Korean residents.
Japanese tourists were also affected. The Japanese Embassy in Nepal said five Japanese nationals who joined a local tour were out of contact. Japanese Prime Minister Sanae Takaichi said the embassy had tried to reach the tourists but was unable to, and had requested a search. Japan's Foreign Ministry is in touch with the families and gathering information.
Nepal's government has asked neighboring India and China for help with rescue operations. Indian Prime Minister Narendra Modi spoke by telephone with Nepalese Prime Minister Balendra Shah and pledged all possible forms of humanitarian assistance. Chinese President Xi Jinping said the most urgent task was to devote all efforts to searching for and rescuing the missing.
Rescue work has been hampered by rugged terrain and severed roads and communication networks. More than 5,000 rescue personnel, including Nepalese soldiers and police, have been deployed, searching for survivors by helicopter and delivering emergency relief supplies such as food and tents. The United States, the United Nations and other members of the international community have also begun emergency assistance.
China is warning of a second flood, as a lake formed by blocked river water remains in Gyirong County in the Tibet Autonomous Region, upstream of the affected area. Another collapse or a sudden release of the blocked water could again cause heavy damage downstream.
