A devastating landslide and flood struck Nepal on Wednesday when a powerful flow of water, rocks and mud rushed through a Himalayan river valley, sweeping away homes, bridges, roads and people. Scientists are still determining the precise cause, but preliminary assessments suggest part of a glacier and an adjoining steep mountainside collapsed thousands of feet above the ground. The debris volume was estimated at roughly 70 Great Pyramids of Giza.

Experts say the event could not have been predicted in advance, but rapid glacier failures are becoming more common in a warming world. Kathmandu University glacier specialist Mohan Bahadur Chand said all glacier regions face risks as warming and melting accelerate. Hazards can range from sudden floods to megatsunamis, depending on where a collapse occurs. A 2019 study identified 210 Himalayan glacial lakes as potential threats to settlements through sudden flooding.

Specialists say monitoring, hazard mapping, community preparation and clear communication can reduce deaths. In Blatten, Switzerland, residents and livestock were evacuated nine days before a 2025 collapse buried much of the village, leaving no residents dead. Experts are working with Nepalese authorities to identify potential collapse sites, map risks and develop local preparedness plans, though Himalayan monitoring remains difficult and costly.