Permafrost, the icy glue that holds the mountains together, is thawing along with the glaciers. This is what increased rockfalls onto the Birch glacier near the Swiss village of Blatten. In May 2025, the glacier fractured, burying the village under 20 million tonnes of rock and ice, and killing a shepherd. Experts monitoring the glacier evacuated 300 inhabitants nine days before the collapse.
Last month, researchers showed that laying a fibre-optic cable across a glacier can detect crevasses hidden 25 metres down, a far cheaper way to monitor fracturing than seismometers. They were surprised to discover that 8 per cent of the volume of a glacier in Valais was empty crevasses. Scientists may be underestimating the damage to glaciers’ stability, says Thomas Hudson at ETH Zurich, one of the study’s authors.
In the past, monitoring was really all about protecting the glaciers, he says. “We now need to put more of our focus on monitoring for prevention of disasters.”
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Below, a disaster similar to the Nepalese collapse destroyed a Swiss village in 2025.