Melting Permafrost Is Driving a Record Number of Rockfalls in the Alps This Year

An exceptionally hot summer has driven a record number of rockfalls in the Alps, some fatal, with "a large majority attributable to the climate crisis," says Ludovic Ravanel, a geomorphologist and research director at CNRS, France's national science research center. The Mont Blanc massif, nicknamed the "roof of Europe," has been hit hardest: Ravanel expects rockfalls there this year to reach about 450, well above the previous record of 300 set in 2022, another year marked by heat waves.

"That is an absolutely staggering figure, given that just 10 or 20 years ago, there were only a few dozen," Ravanel said. He attributes the surge mainly to rising temperatures degrading permafrost — ice that has sat "invisible" in rock cracks for thousands of years, acting as a kind of cement holding the mountains together. As temperatures rise, the ice melts and rocks break loose; melting glaciers add to the risk by easing the stabilizing pressure they once exerted on rock walls.

Although temperatures are expected to drop at high altitudes soon, Ravanel said that does not mean stability will return, because heat absorbed over the summer of 2026 will keep penetrating the ground until November, December or even January. "We're expecting the biggest rockfalls to happen this autumn," he said, though less frequently than in summer. Several climbers have died this season, including two Czech tourists killed in July on Mont Blanc's most common route, and a 31-year-old man who died in August; authorities have closed two climbing shelters as a precaution, as in 2022.

Ravanel does not believe access to the high mountains should be fully restricted, describing them as "above all, a place of freedom," and says climbers regulate themselves and take no greater risk in a heat wave than in a cooler summer. In his view, the rise in accidents reflects growing visitor numbers at mountain resorts, not a surge in danger per visit.