Melting Mont Blanc Glaciers Are Triggering More Rockfalls on Climbers

Around Mont Blanc, on the border between France and Italy, scientists and locals are reporting a sharp rise in rockfalls as melting glaciers and thawing permafrost destabilise the mountain slopes. According to Stéphane Bozon, deputy mayor of the French town of Chamonix-Mont-Blanc, rockfalls have become far more frequent since mid-July: "We're mourning our mountain and the way it's changing. It feels like a punch in the gut," he said.

The issue has resurfaced amid renewed attention following the tragic floods of 26 August this year in Nepal and China, triggered when a chunk of glacier and rock collapsed into Himalayan rivers. In the aftermath, AP journalists spoke to scientists and residents about the situation around Mont Blanc.

Record heat at nearly four kilometres above sea level

According to France's national weather service, Météo-France, the average July temperature at the summit of Aiguille du Midi, standing 3,842 metres high, hit a historic record of 3.3 degrees Celsius this year. By comparison, the average for the same month back in 1994 was just 1.6 degrees.

"It used to snow at high altitude — now it rains," said Wanda Bonardo, head of the Italian branch of the environmental organisation CIPRA. She noted this has a direct impact on the stability of the mountain terrain.

Permafrost no longer holds the rock in place

Heatwaves have degraded the layer of permafrost that, for thousands of years, held Alpine rock faces together like cement. According to Lombardy's glacier monitoring service, the area covered by local glaciers has shrunk by 40 percent since 1991.

"That doesn't mean all the rock faces will collapse in the coming years or decades, but many of them are on the verge of losing stability and are currently held together only by ice. As the glacier changes, we've seen a huge number of rockfalls this year," says Ludovic Ravanel, an expert on the impact of climate change on mountain snow and ice. A rockfall is officially classified as such when the volume of fallen rock exceeds 100 cubic metres.

Ravanel estimates that this year will see around 400 such events — ten times more than twenty years ago. The only worse year was the "catastrophic" 2022, which saw nearly 300 collapses.

Routes that are no longer passable

Chamonix mountain guide Stuart Macdonald shows tourists during hikes where the glacier stood a year ago and a decade ago — a sight that usually provokes a strong reaction. He himself is stunned by the speed of the glaciers' retreat. Rockfalls have made his job harder this year, forcing him to cancel some routes entirely.

"First you hear the sound, then you turn around and see a huge mass of rocks tumbling down the slope. It can be pretty terrifying," Macdonald describes. He says the scariest part is that rocks are now falling onto trails that tourists were still using at this time of year not long ago. "You look at a route you hiked, say, in July or August last year, and realise it's simply impossible to do now. It's pretty disheartening," he added.

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Around Prague, based on reporting by ekolist.cz