Swiss Glaciers Lose Over 5% of Ice in One 'Catastrophic' Year

Switzerland's glaciers lost more than 5% of their entire ice volume in a single year after a record-breaking European heatwave, the Swiss Glacier Monitoring Network (GLAMOS) reported on Thursday, calling 2026 a "catastrophic year" that has wiped out nearly a fifth of the country's ice in just five years.

The Aletsch Glacier, the largest glacier in the Alps, suffered its biggest-ever melt on record in 2026, according to GLAMOS.

Standing on the Scex Rouge glacier at nearly 3,000 metres above sea level, GLAMOS director Matthias Huss dismantled a four-metre aluminium measuring stake that had been fully buried in ice in late July. By September, more than three metres of it stood exposed above the grey surface. "This is a glacier that isn't surviving," Huss said. "There will be probably no ice in 10 or maybe 15 years."

The annual GLAMOS assessment, produced with the Swiss Commission for Cryosphere Observation of the Swiss Academy of Sciences, is based on detailed September measurements at 23 reference glaciers, extrapolated to the nearly 1,300 glacial formations still found in Switzerland. It found that Swiss glaciers lost about 5.5% of their volume in 2026 — the second-biggest annual melt ever recorded, behind only 2022.

A Winter That Never Came, A Summer That Never Let Up

The report points to a brutal combination: a winter with far too little snow, followed by relentless heat from May through September. According to GLAMOS, snow depths at all elevations in winter 2025/26 were far below the long-term average, ranking among the ten least snowy winters since measurements began.

Every month from May to September brought dry conditions and at least one heatwave. The freezing level — the altitude above which temperatures stay below zero — sat above 4,000 metres on 76 days, more than twice the historical average and a new record. June, July and August were each the hottest such months recorded in Switzerland since measurements began in 1864, according to the Swiss Federal Office of Meteorology and Climatology.

The protective snow cover that normally shields glacier ice from the summer sun had already partly disappeared during the June heatwaves. By September, no snow remained even at 3,500 metres. "Now we are in this new world, in this future, where glaciers are just melting away," Huss said.

Records Fall Across The Alps

The losses were not uniform, but they were severe almost everywhere. The average ice thickness of individual glaciers fell by between 2.5 and 4 metres, while exposed glacier tongues lost as much as 10 metres of thickness in a single summer.

Four major glaciers experienced their biggest-ever melt on record, including the iconic Rhone Glacier and the Aletsch Glacier — the largest glacier in the Alps. The Glacier de Tsanfleuron, near Les Diablerets, lost more than four metres of average thickness, a figure Huss said would have been unthinkable a few years ago.

The 2026 total did not quite surpass the 2022 record, and researchers note two reasons. Many glaciers carried more snow into this summer than they had four years ago, and less dust from the Sahara Desert settled on the ice this year, allowing more sunlight to be reflected rather than absorbed. But the direction of travel is unmistakable: between 2022 and 2026, the melt rate at Switzerland's glaciers was more than twice as high as in any previously monitored five-year period.

Small glaciers are now vanishing entirely. The report notes the disappearance of many small ice bodies, such as the Bella Tola Glacier and the Griessfirn/Plattalvafirn, and researchers even had to reposition measurement stakes on the highest-altitude glaciers after the ice melted away beneath the original sites.

The Rhone Glacier was one of four major Swiss glaciers to experience record melting in 2026 as protective snow cover vanished by September.

What This Means

In total, scientists estimate Swiss glaciers lost around 2.2 trillion litres of water between July and September alone — more than four times the annual drinking water consumption of Swiss households. Huss described the quantity as "difficult to imagine."

That meltwater has one short-term benefit: it eases summer water shortages, feeding rivers and reservoirs precisely when demand peaks. But GLAMOS warns the benefit is shrinking as the ice itself shrinks. Glaciers act as natural water towers, storing winter precipitation and releasing it steadily through dry summers. As they disappear, that buffering capacity disappears with them, threatening future water supplies for drinking, agriculture and hydropower.

The longer trend is stark. Switzerland lost about 10% of its glacier ice volume between 1990 and 2000. In the past ten years, it has lost 27%. Nearly a fifth of what remained in 2021 is already gone. "We are seeing extreme years almost every year now and this is really a worrying situation," Huss said.

GLAMOS stated plainly in its release: "Alpine glaciers have no chance of surviving in the long term under such conditions."

Switzerland's Gries Glacier, among nearly 1,300 glacial formations monitored by GLAMOS, as ice tongues thinned by up to 10 metres over the summer.

What Happens Next

For glaciologists, the immediate work is grim accounting. Monitoring teams will continue tracking the 23 reference glaciers through the coming winter, watching whether snowfall can rebuild even part of the protective cover whose absence doomed this year's ice. Another low-snow winter followed by an early heatwave would, on the 2026 evidence, push losses toward or beyond the 2022 record.

For Swiss water managers and hydropower planners, the report sharpens a planning problem that is no longer theoretical. Reservoir strategies built on predictable glacier melt must now be redesigned for a future where the melt pulse arrives earlier, runs larger for a time, and then diminishes as the ice fields shrink. Communities downstream of vanishing glaciers face both flood risks from new glacial lakes and, within years, reduced late-summer river flows.

And for the Alps themselves, the transformation Huss described — mountains stripped of snow, dark relic ice clinging to rock — is becoming the new normal rather than an exceptional year. "It's not that we are surprised, because we know how fast the glaciers are melting," he said. "But to see the colours of the mountains where there is no snow left, there is just these rocks and these dark glaciers that are a relic from the past… it's just incredible."

Unless the run of record-hot summers breaks, the next GLAMOS report is likely to read much like this one — with a smaller ice cap to report on.