Nepal Avalanche Kills More Than 150, Hundreds Missing

More than 150 people have died and hundreds remain missing after a massive avalanche of water, ice, mud and rocks tore more than 170 kilometers down the Bhote Koshi river valley in Nepal. The valley is the main route between Kathmandu, Nepal, and Lhasa, Tibet. There was barely any warning.

Images of the debris-laden flash flood are striking. Unfortunately, it is not surprising. As a glacier expert, I have closely followed their accelerated retreat worldwide as they melt, as well as the disasters they can trigger.

Early analysis suggests the sudden collapse of a glacier triggered the catastrophe. As climate change intensifies, glaciers worldwide are melting, including in high-altitude regions like the Himalayas. The Himalayas are especially vulnerable, as the steep slopes of many of these very high mountains are made of permafrost — rock and soil frozen for centuries.

As temperatures rise, these slopes are beginning to thaw or destabilize. If an earthquake or landslide occurs, it can trigger a sudden and devastating debris flow. It is too early to say this was the exact cause.