CHAMONIX-MONT-BLANC, France — For centuries, French and Italian mountain communities on the flanks of Western Europe's highest peak have gazed upon seemingly eternal glaciers and snow that gave the colossus its name: Mont Blanc, the white mountain.
But climate warming is dismantling the picture at alarming speed.
Europe's record heat waves this summer savaged permafrost that for millennia has acted like glue on the Alpine landscape. Defrosting cliffs came apart as high-altitude cold gave way to higher temperatures, sending rock falls cascading from the heights. A famously dangerous rock-prone gully that climbers have long braved on ascents to the summit, 4,805 meters (15,766 feet) up, became temporarily impassable.
“We weep for our mountain, the way it's changing. It hits us in the gut,” said Stéphane Bozon, a deputy mayor in Chamonix-Mont-Blanc, a French town at the foot of the giant that straddles France's border with Italy.
“From mid-July onward, we saw an increase in rock falls. We saw areas becoming difficult to access because of glacial retreat and snowmelt on the glaciers, with crevasses opening up and rock collapses making some areas difficult to reach or traverse,” he told The Associated Press.
Each degree of warming can have an outsized impact. On the Aiguille du Midi peak, which rises to an altitude of 3,842 meters (12,605 feet) in the Mont Blanc range, average temperatures for July have soared. From a chilly 1.6 C (33.8 F) in 1994, the monthly average for this July was the warmest ever recorded, at 3.3 C (37.4 F), says Meteo France, the national weather service.
“The mountain really dried out, with temperatures unlike any I had ever experienced,” Bozon said.
The Himalayan flood disaster hits close to home in the Alps
In the wake of devastating floods in the Himalayas, AP talked to researchers, climbers and residents coping with the risks and uncertainties of climate change on Mont Blanc.
The Aug. 26 floods that swept through Nepal and China were triggered after a collapse of bedrock and glacier ice sent debris and water surging through multiple Himalayan rivers. Initial assessments of many scientists are that climate change played a key role in creating conditions for the catastrophe.
As Earth's global average temperature rises because of the burning of oil, gas and coal, the chances of such disasters increase.
In the Alps, glaciers once admired for their icy majesty are being eyed with trepidation as they shrink and lose stability.
Bozon, who is in charge of safety for Chamonix, says his town urgently needs to prepare for “serious scenarios” of chunks of glacier or mountain potentially falling onto inhabited areas.
“We have to move quite quickly because this summer has shaken us and year after year we’re being shaken by the glaciers’ retreat,” he said.
In Italy, researchers are also documenting dramatic damage wrought by heat on glaciers this year. In Lombardy, Alpine glaciers have lost more than 40% of their surface area since 1991, according to the region's glacier service.
“While it used to snow at high altitudes in the past, now it rains,” said Vanda Bonardo, head of the Italian branch of the International Commission for the Protection of the Alps, a nongovernmental organization.
“So we’ve also seen the effects on the stability of the terrain,” she said.
Rock falls in the Mont Blanc area have surged
Permafrost that has held Alpine peaks in its icy grip for thousands of years acts as a cement, helping to hold their steep rock faces together. It took a beating from the succession of heat waves.
“That doesn't mean that all the rock faces will collapse in the coming years or decades but quite a number of them are on the verge of becoming unstable and remain stable today only because of the presence of that ice. As the ice changes, we have seen a huge, huge number of rock falls and rock collapses this year,” said Ludovic Ravanel, a researcher at Savoie Mont Blanc University who specializes in climate change's impact on mountain snows, glaciers and frosts.
A collapse is a major fall involving more than 100 cubic meters (3,531 cubic feet) of rock — more than enough to fill a large shipping container. Ravanel expects this year's tally of collapses in the Mont Blanc massif “will probably reach around 400.” He says that is about 10 times more than two decades ago.
The last time things got close to this bad was the ’’catastrophic year″ of 2022, he said, with nearly 300 collapses.
“This has really been one of the defining features of the summer of 2026,” he said.
A Mont Blanc climbing guide juggles the risks
Chamonix-based mountain guide Stuart MacDonald says it shocks him to see how rapidly and extensively glaciers that hang from the flanks of the Mont Blanc massif are retreating.
When he guides people up the peaks, he points them to “where the glacier was last year and this is where it was 10 years ago. And that usually has quite an effect.”
Melting and the risk of rock falls made his job “pretty challenging” this summer and forced him to cancel plans to lead a group to Mont Blanc's summit last week.
“You hear it before you see it and then you’ll turn round and you’ll just see an enormous cascade of rocks coming down a slope and it can be quite terrifying,” MacDonald said.
“What’s most scary is that sometimes these rocks are falling on routes that we used to be climbing at this time of year,” he added. “It can be depressing sometimes when you look at something that you maybe climbed in July or August in the past and you see that it’s absolutely impossible to do it now.”
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Leicester reported from Paris. Associated Press journalists Trisha Thomas and Paolo Santalucia in Rome and Angela Charlton in Paris contributed.
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