(CNN) -- Summer skiing on high glaciers in the European Alps has been a tradition for decades, but this year's unprecedented heatwaves have fans worried that ski resorts may be forced to permanently shut down lifts during the warm months.
Some high-altitude ski resorts, such as Zermatt and Saas-Fee in Switzerland, Les Deux Alpes in France, and the Stelvio Pass on the Swiss-Italian border, still offer high-altitude skiing during part of the summer.
But human-induced climate change has contributed to successive heatwaves in the Northern Hemisphere between May and August.
High temperatures and the absence of night-time freezing in the Alps have accelerated the melting of glaciers, forcing operators to stop skiing for safety reasons.
For the first time in years, part of the summer season passed without organized lift-accessed skiing anywhere in the Alps.
"It's very sad, because it deprives children's teams and local teams of the opportunity to train," says Simon Wells, a ski coach based in the Swiss village of Zermatt.
Zermatt aims to provide skiing 365 days a year. In typical summer, from May until late October, the resort operates about 21 kilometers of groomed trails, as well as a snow park on the Theodul Glacier near the Italian border.
It can be reached via a cable car that ascends to the top of Klein Matterhorn at an altitude of 3,883 metres, which is the highest lift station in Europe.
Wells describes the experience as magical, as skiers can watch the sunrise from the top of the Alps, while green pastures and valleys extend below, in stunning contrast with the white icy expanses.
Local skiers and international teams come to the area to train in preparation for the season, along with tourists who want to see the Matterhorn and the glaciers or try skiing for the first time. Skiing usually ends around noon, when the snow becomes soft due to the heat.
Obvious changes
This year, Zermatt announced on August 1 that skiing was temporarily suspended due to "persistent high temperatures, absence of nighttime coolness, frequent thunderstorms, and changing snow and glacier conditions."
This was only the second time, after the summer of 2022, that the resort had to stop the lifts for safety reasons.
Wells, who has been involved in snow sports for 38 years, says he has seen clear changes, most notably the shrinkage of glaciers.
He explains that the problem this year was the extreme weather conditions: “One moment there are huge amounts of snow, and then there is intense and continuous heat.” The absence of the usual nightly freeze-thaw cycle also created large boulders and fissures that were previously covered in ice.
In the nearby Saas-Fee resort, which offers more than 19 kilometers of summer ski runs, operations ceased on August 10. Skiing on the Stelvio Glacier was also suspended on August 15 due to persistent heat waves, lack of overnight cooling and refreezing of snow. The operators described the decision as "painful but necessary."
With the closing of Timberline Resort in Oregon on July 19, the last American summer ski destination, the Northern Hemisphere saw a period when summer skiing was nowhere to be seen.
More walkers, less skiers
In the French resort of Les Deux Alpes, the public can ski on the Mont-de-Lance glacier until the end of May, while training for professional athletes continues until early July.
Before 2023, skiing was possible until late August, but the summer heat of 2022 prompted the resort to advance the season with the aim of protecting skiers and preserving the glacier.
In Austria, the long ski season at Hintertex is also starting to wind down, and the resort is turning off skiing for part of the summer and focusing on hikers, families and day visitors.
In the French village of Taines, skiing was available on the Grande-Motte glacier from June 20 to July 20 this year.
Clement Colin, an official at the Mountain and Lift Management Company in Tin, says that conditions were excellent at the beginning of summer, but they became more difficult as the temperature rose.
Tin previously promoted itself with the slogan “365 days of skiing per year,” but the number of ski days has gradually declined over the past two decades. “Summer skiing was popular in the past, but it has declined in recent years. We now have more walkers and fewer skiers in the summer,” says Colin.
Since 1850, Alpine glaciers have lost between 30% and 40% of their area and about half their volume due to rising temperatures. Between 2000 and 2023, glaciers in central Europe, including the Alps and Pyrenees, lost about 39% of their ice.
In Tain, the glacier loses between three and four meters of thickness annually. Colin says the melting is accelerating and the area of ice is shrinking, which leads to more rocks appearing and making the ski trails more difficult to maintain. The glacier is expected to disappear in 10 to 15 years.
The timing is worrying
Swiss glaciers, numbering about 1,400, will lose about 3% of their total volume in 2025, the fourth largest annual decline on record. In the past decade alone, Switzerland has lost a quarter of its glacial ice.
Glacier scientist Matthias Hoss pointed out that the snow that accumulated during the winter on the Swiss glaciers ran out this year by June 29, the second earliest date on record after the extremely hot summer of 2022.
He said the melting snow was not exceptional in itself, but "the timing is worrying," as it is supposed to happen in a month or two.
Colin believes that the change in seasons will force resorts and skiers to reconsider their schedules. Snow may be better in March and April than in January, while summer skiing will gradually move to May and June instead of July and August.
He stresses that resorts will need to adapt by promoting other activities such as hiking and mountain biking, and perhaps encouraging visitors to see glaciers for themselves to understand the effects of global warming.
Wells tries to remain optimistic, saying: “We view mountains as living things and they determine what we will do. Even in winter, the mountain decides. In order to open the glacier again, we need consistently low temperatures and some snow. I am trying to remain as positive as possible.”
