Flash floods triggered by a glacier collapse on the Nepal-Tibet border have resulted in a significant loss of life and widespread damage, officials and experts reported. The disaster, which occurred on Wednesday morning local time, swept through the region along the Trishuli River, also known as the Bhotekoshi, carrying mud, water, and debris that destroyed homes, roads, bridges, and power infrastructure.
Nepali authorities reported that 403 people are missing in Nepal, including 341 foreign nationals from countries such as India, the United States, the United Kingdom, Australia, South Korea, and Malaysia. Chinese state media confirmed at least three fatalities in Tibet and reported 265 people missing.
The flash flooding was caused by a sudden landslide of ice and rock from a glacier collapse, which propelled a surge downstream along the Lhende Khola river, a tributary of the Bhotekoshi. Researchers from the International Centre for Integrated Mountain Development in Kathmandu noted that water levels in the Trishuli River rose nearly nine meters within 30 minutes. This area has experienced similar flooding twice in the last 14 months due to ice and rock avalanches blocking and then releasing the river.
Initial suggestions by Nepal’s foreign minister, Shisir Khanal, that an earthquake may have triggered the landslide were later contradicted by the U.S. Geological Survey (USGS). The USGS clarified that no earthquake occurred; instead, a glacial collapse and subsequent debris flow registered seismic activity equivalent to a magnitude 5.2 event. This collapse took place at 8:37 a.m. near the Nepal-China border.
Satellite imagery reviewed by University of Calgary geomorphologist Daniel Shugar indicated that a 0.2 square kilometer section of the glacier fell approximately 1.2 kilometers vertically. Warmer temperatures, evidenced by rapid snowmelt in the 24 hours before the event, could have contributed to the instability. Construction activity in the region was also suggested as a possible factor influencing the collapse.
Glaciologist Andrew Mackintosh of Monash University described the event as triggering a complex chain reaction, where massive volumes of water combined with sediment to create the fierce flooding. An international group of researchers noted that while the glacial collapse was central to the incident, other contributing factors may have been involved.
Experts emphasized that such large glacier collapses remain relatively rare but may become more frequent with ongoing climate change. The Himalayas, encompassing Nepal, India, China, Bhutan, and Pakistan, are warming at twice the global average rate, increasing the risk of avalanches, landslides, and floods. The United Nations reported in 2023 that Nepal’s mountains have lost nearly one-third of their ice cover over the past three decades. Glaciers in the Hindu Kush Himalayan region have been retreating faster in the last decade compared to previous years.
Similar glacier-related disasters have occurred in recent years, including a 2021 glacier collapse in India’s Uttarakhand state that left around 200 people dead or missing. Additionally, experts highlight the threat posed by glacial lake outburst floods, which occur when natural dams formed by glacier melt give way, releasing large volumes of water downstream. Nepal has more than 2,000 glacial lakes, with 21 identified as potentially hazardous.
As rescue and recovery efforts continue, authorities are facing the challenge of responding to a disaster whose scale and impact underscore the growing vulnerabilities of mountain communities in a warming climate.