Experts Identify Likely Cause of Deadly Nepal Mudslide as 1,400 Remain Missing

Devastating floods that swept through Nepal and Tibet, leaving hundreds feared dead, were likely set off by a huge glacier collapse and fast-moving debris flow that seismic instruments recorded as a magnitude 5.2 landslide, the U.S. Geological Survey said.

The USGS had initially attributed the deadly mudslides to a magnitude 4.4 earthquake. But the agency later revised that assessment after reviewing readings from nearby seismic stations, long-period seismic waves and satellite imagery. The updated data indicated that an earthquake had not taken place.

Climate specialists at the Kathmandu-based International Centre for Integrated Mountain Development told The Associated Press that Wednesday’s sudden flash floods were probably caused by a glacial avalanche.

“Hydrological observations indicate the exceptional speed and magnitude of the flood wave,” the experts said in a statement. At one stage, they noted, water levels on the Trishuli River surged by as much as 27 feet in just 30 minutes.

More than 360 people are now estimated to have died in the flooding along the Nepal-China border, the AP reported, citing local police.

Search-and-rescue crews are continuing to look for more than 1,400 people reported missing after the disaster. Many of those unaccounted for were foreign visitors and pilgrims.

Nepal Police began releasing lists Thursday of missing Nepali citizens and foreign nationals. Several dozen Americans were among those named.

A U.S. State Department spokesperson confirmed to Fox News that as of 8 a.m. Thursday, there are approximately 90 Americans who may have been impacted by the floods. The U.S. embassies in Nepal and China are working to assist Americans in affected areas.

“The State Department is closely monitoring the situation and has deployed a disaster response advisor to the region to support response efforts,” the spokesperson said. “The Department will also provide $500,000 in assistance through its global award with Catholic Relief Services, supporting emergency shelter, relief items, and water, sanitation, and hygiene assistance to flood-affected communities in Nepal.”

The Nepalese army rescued more than 100 people from flood-hit areas by helicopter Thursday morning, according to army spokesperson Brig. Gen. Raja Ram Basnet.

The flooding destroyed dozens of bridges and nearly 25 miles of roads, further complicating search and rescue efforts, according to Nepalese officials.

Bishal Kumar Bhandari, chairman of the Nepal Red Cross Society, told the AP that they have shifted focus to large-scale relief operations. He said that around 1,200 people were displaced from at least three villages.

Videos of the disaster showed raging floodwaters sweeping away cars, engulfing people trying to flee and destroying homes and bridges.

Debris was left tangled in tree branches and power lines, vehicles were buried and mud-covered survivors emerged as flooding cut off travel in some areas.

The village of Soley in Nuwakot, which has about 25 homes, was almost entirely destroyed, according to Kathmandu-based journalist Nirajan Paudyal, whose parents and other relatives live there. Desperate for news, he traveled to the area Thursday to check on his family.

“There is no update till now. I fear there won’t be any update,” Paudyal told the AP.

The Dalai Lama, the highest spiritual leader of Tibetan Buddhism, released a message to those affected by the floods in the region.

“I am saddened to learn of the devastating floods in the Rasuwa region of Nepal and Kyirong in Tibet, resulting in loss of life and heavy structural damage,” the 91-year-old leader said in a statement. “I pray for all those who have lost their lives, and offer my sympathy and heartfelt condolences to the bereaved and to all those affected by this tragedy.”

He continued: “Since this region has seen calamities in the past as well, these are certainly symptoms of a deeper underlying cause — whether climate change or other factors. I hope that appropriate follow-up measures will be taken, wherever possible, to help ensure that such disasters do not recur.”

The disaster in Nepal and Tibet underscores a broader threat, as increasingly unstable Himalayan ice poses risks to communities, infrastructure and water supplies across one of the world’s most densely populated regions.

The region experienced similar flash flooding in August 2025, when high temperatures caused a glacial lake in Tibet to overflow. The resulting floods killed nine people and damaged critical infrastructure, including a bridge linking Nepal and China.