By Lili Pike, Lou Del Bello and Bloomberg Green Daily.
Scientists are pointing to a glacier collapse as the cause of a devastating flash flood that killed at least 350 people and left many more missing near Nepal’s border with China, a mountainous region that’s increasingly imperiled by the effects of man-made climate change.
Initial assessments based on seismic and satellite data, as well as videos of the event, indicate that a very large section of a glacier detached and collapsed. That in turn caused seismic waves equivalent to a 5.2 magnitude earthquake, according to the US Geological Survey. Ice from the glacier may then have blocked the Lhende Khola river, causing water to quickly accumulate and ultimately surge downstream.
“What we’ve certainly confirmed – there was a large ice avalanche, probably a mixture of ice and rock, which detached and then became fluid and then transformed into this devastating flood,” said Simon Allen, a research associate at the University of Zurich who studies glacial hazards in the Himalayas.
Nepal is particularly vulnerable to flash floods because of its mountainous terrain and rapidly melting glaciers. Such events are becoming more frequent as global warming accelerates the ongoing thaw in the Himalayas, an area that holds more snow and ice than any place on Earth besides the Arctic and Antarctica. The development has a cascading effect — from mudslides to water scarcity — for the nearly 2 billion people living downstream from Himalayan-fed rivers, according to the United Nations.
Himalayan glaciers melted 65% faster between 2010 and 2020 than during the previous decade, the UN said, while the risk of glacial lake-related flooding across the broader Hindu Kush Himalaya region is expected to roughly triple by the end of the century.
“When you put together all the physical understanding that the glaciers are retreating, permafrost is thawing, it certainly adds up,” said the University of Zurich’s Allen. Experts are concluding “that we are seeing and we are expecting these events to become more frequent,” he said.
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