A record heat wave that swept across Europe this past summer had some harsh consequences in Chamonix. With temperatures soaring into the mid-90s (about 15 degrees above normal) in July and August, increased rockfall from rapidly melting ice and snow caused dangerous conditions for hikers and climbers, even closing a popular route to the summit of Mont Blanc. In fact, Europe's highest peak, like others in the Alps, is literally crumbling from the heat—it measured two meters lower than it did two years ago, thanks to the loss of permafrost that usually holds the rock together.
Besides a mild previous winter and climate change in general, Chamonix's summer heat wave is also affecting skiing. High temperatures sped up the melting of the already retreating glaciers—by 10 centimeters per day in July instead of the average 3 centimeters per day—and created more, deeper open crevasses on classic ski descents such as the Vallée Blanche that prove more difficult to fill in once the snow flies.
Europe's highest peak, like others in the Alps, is literally crumbling from the heat.
Meanwhile, near the 10,800-foot summit of the Grands Montets ski area, the Rognons glacier stayed cool and preserved. The reason? A 7,500-square-foot, heavy-duty tarp, stretched over the top of the glacier from May to October. It's the fifth summer that Grands Montets has used this massive sheet of polyester and polypropylene to repel the effects of the sun and warmer-than-normal temperatures, essentially preserving skiing on Chamonix's most iconic ski domain.
"We have been able to preserve two to three meters of ice with the tarp," said Pascal Croz, ski patrol director at Grands Montets. "And in summers past it didn't have an effect as important as it did this summer."
The Rognons glacier plays a critical role in the winter. Starting at the bottom of the stairs that descend from the summit tram, the ice field serves as the entry point to the vast, storied ski terrain of the back side of Grands Montets, where the majority of skiers and snowboarders schuss and where backcountry enthusiasts start their routes to the snow-blanketed upper cirque of the valley, ringed by towering spires (called aiguilles, or needles in French) and steep powder-filled couloirs.
The tarp, first installed in the summer of 2011, prevents the glacier's upper snow layer from melting and bergschrunds from opening. Without adequate snow and ice cover, access to the pistes would be, at a minimum, dangerous, and certainly more difficult, if not impossible.
"The tarp has been very effective," said Luc Moreau, Chamonix's resident glaciologist who has been studying area glaciers since the mid-1980s.
It was after the record low-snow season of 2010-2011, when Grand Montets ski patrollers spent a lot of time pushing snow into the bergschrund, that they suggested the idea of a summer ice cover. In the past, said Croz, snow had always covered the Rognons glacier through the summer, but that wasn't the case by 2011. A tarp wasn't a revolutionary idea—several Swiss ski areas had been covering glaciers for years—but the simplicity of the solution belies the complexity of the issue.
And while there have been plenty of good snow years amidst the melting—and there will likely be more—it's really what happens in the summers that impacts the winters.
A warming climate and retreating glaciers have been changing the landscape of the Alps for three decades—that's no secret. And most people are aware that the warming has accelerated in the last decade or so. Glaciers in the Mont Blanc region lost some 33 feet of thickness between 2003 and 2012.
But acceleration is an issue because, not unlike living organisms—which they're often compared to—glaciers must maintain an equilibrium to stay healthy. If, at the end of the summer, a glacier has lost more than 60 percent of its snow cover, it compounds the losses and causes the ice to melt even faster. The Argentière glacier, which forms the boundary of the Grands Montets ski domain and which the Rognons glacier feeds into, had only 30 percent snow cover at the end of the 2004 through 2009 melt seasons. Its tributary glaciers lost all their snow cover during three of those years, contributing to even further losses in the main stem of the glacier.
And while there have been plenty of good snow years amid the melting—and there will likely be more—it's really what happens in the summers that impacts the winters, said glaciologist Delphine Six.
"The future projections show a rise in temperature, and it is this rise in summer temperatures that will make glaciers melt more," said Six, a researcher and teacher at the University of Grenoble. "There will be more snow in winter at these altitudes in the future. But because strong summer melting is expected, the shape of the glaciers will evolve, and it will require even more vigilance because of the crevasses that might appear. That's why these tarps will become even more important."
Across the massive, above-treeline expanses of the Alps, glacier tarps can only influence a tiny fraction of ski areas' terrain, and they'll likely never touch the way out-of-bounds lines that draw adventurers from around the world. Increasingly unpredictable, yo-yo-like winter weather, a deeper permafrost layer, and increasing rockfall is making some of Chamonix's classic backcountry ski routes more dangerous, said longtime local guide Grisha Kravtchenko, making his job more complicated. Kravtchenko cites the Col du Chardonnet, at the top of an offshoot of the Argentiere glacier on the Haute Route, where melting permafrost has made an already steep crossing even more precarious, and the north face of Mont Blanc, where the route is increasingly technical because of hanging seracs.
"We need to live with it," said Antoine Burnet, sales and marketing director for the Companie du Mont Blanc, which runs several Chamonix valley ski areas. Climate change "is not something we can control or stop."
But the ski company, which recently joined the Mountain Collective Pass, is planning its future with climate change in mind. Blessed with more high-altitude terrain than most European ski areas, it is pouring more resources into developing that terrain, not just for experts but for a wider range of skiers. And it's hedging its bets by expanding the range of non-ski activities—just getting people to the top of the Aiguille du Midi or to on-mountain restaurants for lunch will help spread the word that there's still plenty of snow in Chamonix.
Meanwhile, skiing as we know it continues on a tiny sliver of the ski world, thanks to a football-field-length piece of fabric.