High mountain glaciers formed in the ice age are retreating and becoming unstable as the burning of fossil fuels heats the climate and leads to a decline in snowfall. The instability creates the conditions for large glacial sections to collapse, triggering ice and rock avalanches that can dam river valleys before tidal waves of water are released.
Following the glacier collapse that triggered what is known as a mountain tsunami in Nepal and Tibet on August 26, thousands are still missing and feared dead. Unlike the 2025 glacier avalanche that destroyed the town of Blatten in Switzerland — where nearly all inhabitants were evacuated — a lack of early warning systems in the Himalayas left locals and tourists at the mercy of flash floods.