Industry News
Europe’s high-alpine zones just experienced something that’s never happened this early in the year: temperatures above freezing at nearly 5,250 meters (17,200 feet). In a record-shattering heat event, the “thermal zero”—the elevation where temperatures in Celsius drop below freezing—climbed to its highest ever recorded level for the month of June. On June 28, a Swiss weather station in Payerne measured the freezing point at 5,136 meters (16,850 feet). Just a few hours later, a station in Cameri, Italy, clocked it even higher at 5,233 meters (17,170 feet).
To put that in perspective: Western Europe’s highest peak, Mont Blanc, tops out at 4,810 meters (15,780 feet). Which means that during this event, even the summit of Mont Blanc sat in air warmer than 32°F.
Worst of all, this is only the start, as it is still June and temperatures are bound to get hotter. A high-alpine weather station located at Colle Major—4,750 meters (15,584 feet) up on Mont Blanc—reported a daytime high of 3.7°C (38.7°F) on June 28, and even the overnight low stayed above freezing at 1.1°C (34°F) on June 29. That’s 24 straight hours of above-freezing temperatures at nearly 15,600 feet.
The thermal zero (or freezing line) is a key weather metric that tells us how high you need to go in the atmosphere before you hit freezing temperatures. In summer, that altitude usually sits between 3,200 and 3,500 meters (10,500–11,500 feet). Climbs to 4,000 meters (13,120 feet) used to be rare—now they are routine. Over the past five years, Europe has watched its thermal zero rise further and more frequently than ever. But this event—hitting over 5,200 meters in late June—is something new entirely. Meteorologists say it’s the highest June thermal zero ever recorded, and the fifth highest in any month.
Why does this matter for skiing and snowboarding? Because when freezing levels sit higher than the peaks, snow melts—fast. That affects glacier health, snowpack retention, and even safety in the mountains. Skiers and snowboarders used to treat extreme summer heat in the Alps as a one-off anomaly. Now it appears to be a pattern. For North American powder hunters who chase winter year-round the message is clear: climate change is climbing up the mountains faster than expected. And the snow line is going with it.
Meteorologists are blaming a persistent African anticyclone that’s pumping hot, dry air across southern Europe. The heatwave is expected to last into early July, possibly pushing the freezing line even higher—beyond 5,400 meters (17,716 feet).
The effects are clearest in the Alps. For decades, 60% of Italy’s glaciers have already melted. But now the danger is no longer just about slow retreat, it’s about structural collapse. This month, a glacier collapse buried the town of Blatten, Switzerland. In 2022, part of the Marmolada glacier broke apart during a heatwave, killing 11 climbers.
Climbers and ski mountaineers are being urged to check forecasts and avoid high-elevation travel without consulting official warnings. As Meteo Valle d’Aosta, the regional Italian weather agency for the Aosta Valley, put it, “What we’re seeing isn’t just unusual. It’s historic.”
