Swiss Glacier Melt Rates: A Timeline of Accelerated Loss

2026: 5.5% gone, second only to 2022

GLAMOS and the Swiss Academy of Sciences report that Swiss glaciers lost about 5.5% of their remaining ice in the 2025/26 glacier year, the second-largest percentage decline on record. Over five melt seasons, 2022 to 2026, Switzerland lost nearly a fifth of its glacier ice. Average ice thickness fell 2.5 to 4 metres; some glacier tongues lost up to 10 metres. The Allalin, Clariden, Rhône and Aletsch glaciers saw record melt. Between July and September, about 2,200 billion litres of meltwater ran off, more than four times Swiss annual drinking-water use.

“Alpine glaciers have no chance of surviving in the long term under such conditions,” said GLAMOS head Matthias Huss. “What used to be extreme events, by definition rare and very intense, now occur almost every summer.”

Plattalva declared extinct

The Plattalva Glacier disappears completely in September and is declared extinct. Around 30 small glaciers are estimated to have vanished during 2026, bringing the total since 2016 to about 160. On the Great Aletsch Glacier, the lowest monitoring point records about 13 metres of ice-thickness loss for the year.

Glacier Loss Day comes early

By 29 June the average Swiss glacier has already melted all the snow it gained over winter and starts losing older ice, an extremely early Glacier Loss Day. From May to September the 0°C level sits above 4,000 metres for 76 days, more than double the average. Between mid-June and mid-July the Rhône Glacier thins by about 4 metres.

Thin snow, no protection

Snowfall over winter is well below the long-term average at all elevations. Thin snow matters twice: it adds little new mass, and it disappears early, exposing darker ice that absorbs far more sunlight.

2025: 3.0% lost, a quarter in a decade

GLAMOS reports a loss of about 3.0%, or 1.4 km³, the fourth-largest percentage loss since detailed observations began in the 1950s, after 2022, 2023 and 2003. After a winter about 13% short of snow, a June heatwave (the second-warmest June after 2003, and the warmest ever recorded at the Jungfraujoch) pushed glaciers toward 2022 levels before a cooler July with fresh snow avoided the worst. Switzerland holds about 45.1 km³ of ice, roughly 30 km³ less than in 2000, and glacier area is down about 30% to around 755 km².

Birch Glacier collapse buries Blatten

The Birch Glacier, overloaded by millions of cubic metres of rock that had fallen onto it from the Kleines Nesthorn, collapses. Ice, rock and debris bury most of the village of Blatten. Its roughly 300 residents had been evacuated on 19 May after geologists warned of the risk; one 64-year-old man was killed. The cause was rock loading rather than melt, but the event made mountain hazards in a warming Alpine environment national news.

2024: a snowy winter is not enough

Winter 2023/24 brings about 30% more snow than average, and conditions stay favourable into June. Then a hot July and August, and heavy Saharan dust on the snow, accelerate melt. August 2024 records the largest monthly loss ever measured for that month, and the year ends with about 2.5% of the ice gone.

2023: a second extreme year

Another low-snow winter and a hot summer strip about 4.4% of the remaining ice (first reported as about 4%). In two years, Switzerland loses about a tenth of its glacier ice, as much as in the three decades from 1960 to 1990.

2022: the record year

The modern record. A winter with little snow, Saharan dust that darkened the snowpack in spring, and a long, hot summer combine. Swiss glaciers lose about 5.9% of their volume (first reported as roughly 6%), with an average mass balance of about minus 3.1 metres water equivalent. Snow vanishes even from summit levels, and glacier fronts collapse into rock and meltwater.

The most negative decade

GLAMOS calculates that Switzerland lost about 24% of its ice volume in the ten years to 2025, against 17% in 2010 to 2020, 14% in 2000 to 2010 and 10% in the decade to 2000. The periods 2010–2020 and 2015–2025 overlap, but the trend is unambiguous.

The European heatwave summer

The record European heat of 2003 produces one of the worst glacier years then measured. June 2003 remains the benchmark: GLAMOS ranked June 2025 second only to it. 2003 stayed a reference point until it was overtaken by 2022, 2023 and, in 2026, again.

About 75 km³ of ice

At the start of the century Switzerland holds roughly 75 km³ of glacier ice, by GLAMOS’s reconstruction. Annual losses in the following two decades mostly run between about 0.5% and 2.5% of the remaining volume.

More than 1,000 glaciers vanish

Comparing glacier inventories, researchers find that more than 1,000 Swiss glaciers disappeared completely between 1973 and 2016, and about 100 more between 2016 and 2022. Most were small, but they are the first part of the system to go.

Detailed Swiss-wide observations

More glaciers come under regular, detailed mass-balance observation. The 2022, 2023 and 2026 rankings are made against this record; GLAMOS excludes slightly larger estimated losses in 1921, 1928 and 1947 because measurements then were too sparse.

The Claridenfirn series begins

Measurements of snow accumulation and melt begin on the Claridenfirn in canton Glarus. More than a century later the series still runs, and in 2026 it recorded another year of record melting.

Systematic length measurements

Scientists begin measuring where glacier fronts end each year, and in 1893 the Swiss natural science society sets up a glacier commission to coordinate the work. Annual length-change reports, today published as the Swiss Glacier Bulletin, become the backbone of the national record.

End of the Little Ice Age

After centuries of a cooler climate, many Alpine glaciers reach their last major high stand around the middle of the 19th century. The Rhône Glacier reaches down to the valley floor at Gletsch. From here, retreat dominates, interrupted by small advances in the 1910s–1920s and 1970s–1980s.