On June 29, 2026, the snow accumulated by Switzerland’s glaciers over the course of the previous winter had melted. Known as Glacier Loss Day, this date marks the point at which further melting begins to erode the glaciers’ mass, until snow accumulation resumes in the fall. Matthias Huss, the network head of Glacier Monitoring in Switzerland (GLAMOS), told Agence France-Presse (AFP) that this year’s Glacier Loss Day was “three months too early, compared to a healthy state.”
Modeled on Earth Overshoot Day, Glacier Loss Day serves as both a benchmark of the glacier’s health, and also an indicator of broader annual warming trends across the Alps. This year’s Glacier Loss Day was the second earliest on record, falling only three days later than it did in 2022—a year in which glaciers lost about six percent of their mass overall.
Experts suggest that this year’s early and rapid melt is largely a product of two consecutive European heatwaves in June and July, which pushed temperatures above 40°C (104°F) in parts of central Europe. The daytime freezing level in parts of the Alps rose to 4,500 meters in June, and even at high altitude there was little overnight refreezing, leading to risks including higher avalanche likelihood and slope instability.
In the Mont Blanc massif in the French Alps, aerial imagery shows that the Bossons Glacier, which looms above the resort town Chamonix, is experiencing extensive glacial melt. In areas where the glacier’s ice touched the valley floor in the 1980s, meltwater streams are now visible flowing down the rock alongside the receding glacier. Moreover, a large hole first spotted in the lower tongue of the glacier in 2025 remains visible over a year after it was first identified. This could be due to the significant reduction in snowfall compared with the 2010-2020 average: snow depths in the central European alpine region during the 2025-26 winter season are among the five lowest seen in the last three decades. With less snow to reflect sunlight, more of the glacier’s darker, older ice is exposed. That ice absorbs more sunlight than snow due to its lower albedo, so its exposure accelerates overall glacial melt.
The Rhône Glacier, located in the southern Swiss Alps, lost over four meters of ice thickness in June and July of this year. As of July 2026, GLAMOS reports the glacier is losing an average of 10 centimeters of ice per day. As meltwater widens cracks and hollows into cavities, more are expected to appear near the glacier’s lower zone, much like at Bossons. The consequences extend beyond the glacier itself: the Rhône Glacier’s meltwater feeds the Rhône River, which runs for over 500 miles through Switzerland and France. Roughly 2.5 million people rely on the Rhône for their drinking water, with millions more dependent on the agriculture it supports. In the short term, accelerated glacial melting leads to higher early season run-off—a beneficial side effect given central Europe’s current drought. However, if the glacier continues to melt as forecasted, the Rhône catchment is likely to face severe water security issues during the later summer months when glacial ice mass no longer contributes significantly to streamflow. As a result, the Rhône is no longer able to sustain the flow volumes that communities further downstream have long depended upon, especially in mid- and late summer
At the Grande Motte Glacier, located at the highest point of France’s Tignes ski resort (3656m at its summit), the elevation allows for limited “summer skiing” in June and July across 12 miles of trails spanning the glacier. This year, the usual month and a half long summer skiing season ended earlier than usual, due to unsafe conditions brought about by a lack of snow on the slopes, according to the resort.
While Tignes is still planning to open for its winter season at the end of November as usual, the future of the Grande Motte glacier, which constitutes a quarter of the resort’s overall terrain, is uncertain. In an interview with France 3, Clement Colin, the CEO of Altta—the company responsible for managing Tignes’ ski lifts—said people “would not be skiing on the glacier for much longer… [and summer skiing could] disappear within 10-15 years.” In an attempt to mitigate the loss of the summer ski season, the resort placed artificial snow machines at the lower perimeters of the glacier runs in 2013.
In an interview with GlacierHub, Jeffrey Schlegelmilch, a professor at the Columbia Climate School and faculty director of the National Center for Disaster Preparedness, refers to this kind of short-term fix as a form of “maladaptation,” one which “buys a ski season a few more years while locking a community deeper into an economy that is going away.”
In Italy, a similar tension has arisen in another important part of the Alpine economy—mountain guiding—as several operators have suspended their use of the Miage Glacier route up Mont Blanc following the June heatwave. Alex Campedelli, president of the Courmayeur Guides Society, told AFP that, owing to the June heatwave, “conditions deteriorated quickly,” meaning it is currently “no longer safe enough to take clients up there.” This change is in large part due to the increasing risk posed by crevasses, deep cracks which form with the shifting ice as glaciers move. Crevasses widen as surface summer meltwater drains through the ice, which heightens the risk they pose to mountaineers who may lose their sense of direction on a rapidly changing glacier.
With the frequency and intensity of heatwaves predicted to drastically increase over the next century, glaciers and the alpine economies they support are likely to be among the earliest and most visible casualties of global warming. The unusually early Glacier Loss Day this summer previews what is to come: researchers predict that 97% of European glaciers face extinction by 2100 if temperatures rise more than 2.7 degrees Celsius above pre-industrial levels. This year alone GLAMOS estimates 20 to 30 small Swiss glaciers may lose their remaining ice entirely.
Central European alpine communities have already been forced to adjust to the changes brought from melting glaciers, with guiding routes being altered and downstream communities at risk, and will likely need to continue to adapt if rising temperature trends continue. As Schlegelmilch puts it, “for mountain communities, the more useful question is usually not how do we keep this summer from happening again” but rather “which of these changes are permanent, and what the local economy and local infrastructure need to look like on the other side of them.”
