At 8.37am on a Wednesday morning, a mass of rock and ice detached from a mountainside in Nepal's Langtang national park, roughly 60 kilometres north of Kathmandu, and dropped 1,200 metres to the valley floor. The debris moved at speeds approaching 150 kilometres per hour, tearing through the Lhende Khola valley and surging into the Bhotekoshi and Trishuli river systems that thread between Nepal and Tibet. Along the Trishuli alone, water levels climbed nine metres within half an hour.

By the time rescue teams reached the area, the death toll was approaching 1,000, with more than 4,400 people reported missing on both sides of the border. Initial confusion over the cause — early reports pointed to an earthquake, while others suggested a glacial event — was resolved by subsequent satellite analysis, which revealed that the bedrock beneath a glacier had given way. The landslide registered as a magnitude 5.2 seismic event.

Adrian McCallum, a senior lecturer in geotechnical engineering at the University of the Sunshine Coast in Australia, described the situation plainly: "It seems that a massive rock face with the glacier on top of it has essentially gone." One seismologist characterised the slide as among the largest recorded anywhere on Earth in the past two decades. Recovery operations have been complicated by poor road access, persistent bad weather, and the presence of two lakes that formed behind the debris field and continue to threaten further flooding downstream. Homes, bridges, roads, and power infrastructure across both Nepal and Tibet have been swept away, severing communities from outside help.

Nepal's Prime Minister Balendra Shah was direct about the wider context, arguing that the Himalayas — shared by Nepal, India, China, Bhutan, and Pakistan — are warming at roughly twice the global average rate, making events like this increasingly probable.