Glacier collapse likely triggered Nepal-Tibet disaster, experts say

A catastrophic flood that swept through Nepal and Tibet, killing at least 180 people, was likely triggered by a massive glacier collapse, according to scientific analysis.

Experts believe a huge chunk of ice, estimated to be between half a million and tens of millions of cubic meters, fell thousands of meters from a glacier into a valley. This event, occurring around 8:37 am local time, registered as a 5.2-magnitude seismic event, initially mistaken for an earthquake.

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A large chunk of glacier fell from about 5,200 metres… into a valley.

"A large chunk of glacier fell from about 5,200 metres… into a valley," said Simon Cox, principal scientist at New Zealand’s GNS Science. "It transformed into this raging mass of debris… where it picks up rocks and sediment and trees and anything in the way and fires it on down through the canyon."

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It transformed into this raging mass of debris… where it picks up rocks and sediment and trees and anything in the way and fires it on down through the canyon.

The resulting wall of water and debris first impacted a border post, captured in terrifying CCTV footage, before surging downstream into Nepal. It flooded villages, destroying bridges and buildings.

With much of the affected region inaccessible, scientists are relying on satellite imagery and ground measurements to understand the disaster. Lauren Vargo, a glaciologist at New Zealand’s Victoria University of Wellington, explained that they can "look at satellite imagery taken before and after the event, and try and see what has changed, essentially looking for what is missing from the mountains in the ‘after’ imagery."

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We can look at satellite imagery taken before and after the event, and try and see what has changed, essentially looking for what is missing from the mountains in the ‘after’ imagery.