When a mountain falls: How ice and rock triggered Nepal’s catastrophic flood – and why climate change is raising the risks

A rockfall in the Himalayas triggered a catastrophic flood that killed hundreds in Nepal on Wednesday, and the danger didn't end there. According to The Conversation, a mass of bedrock and glacier ice broke off near Langtang Lirung and slammed into the valley below, an impact strong enough to register as a magnitude five point two seismic event. The falling debris likely dammed the river temporarily, and when that blockage gave way, a wall of water swept through towns and knocked out roughly a dozen hydropower facilities. Days later, a new debris-dammed lake formed at the China-Nepal border and burst on Friday, sending the river surging again and briefly halting helicopter rescues. Scientists point to thawing permafrost and accelerating glacier melt as the underlying trend making these sudden mountain collapses more frequent across the Himalayas.

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