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When 247 million cubic feet of snow and ice collapsed off a glacier in the dry, mountainous region of western Tibet in 2016, the roiling mass took with it nine human lives and hundreds of animals, spreading more than five miles in three minutes at speeds of nearly 200 miles per hour. The event surprised scientists, who had seen a collapse that big and that fast only once before.

And then it happened again, three months later, on a neighboring glacier, though without fatalities. Glaciologists hadn’t quite believed that glaciers could behave this way, and suddenly they had witnessed two similar collapses in a year.

An analysis of the events, published this week in the journal Nature Geoscience, found that climate change was the culprit in both collapses. The study suggests that in addition to the known risks posed by a warming climate, such as sea level rise, we may also be in line for some cataclysmic surprises.