Swiss glaciers are emerging from winter with unusually little snow, leaving them poorly protected ahead of the summer melt season.
According to the latest report from the Swiss Glacier Monitoring Network (GLAMOS), measurements taken on 25 glaciers in April and early May showed significantly below-average snow cover. Snow depth ranged from one to four metres depending on the region, but overall glaciers held around 25% less winter snow than the average recorded between 2010 and 2020.
Snow acts as a protective layer for glaciers during the warmer months. The thicker the snowpack in spring, the longer underlying ice is shielded from summer heat. Thin snow cover therefore leaves glaciers more vulnerable to melting.
If we have less snow, it disappears more quickly once temperatures rise, said Matthias Huss, head of GLAMOS. That means glacier mass loss begins earlier and is likely to be more severe if summer temperatures are as high as in recent years.
Dry winter, early melting
The main reason for the low snow cover was a lack of winter precipitation. Temperatures matter less for glaciers during winter because conditions at high altitude generally remain below freezing.
Apart from a few brief periods, this winter was exceptionally dry, echoing conditions seen in 2022 and 2023. Those years also brought unusually low snowfall on glaciers and record levels of melting.
April compounded the problem. The month was both warm and dry, and glaciers accumulated little fresh snow. Normally, snowfall at high altitude continues well into spring even after temperatures rise in lower regions.
As a result, some glacier tongues have already begun melting unusually early. Although early melting has occurred before, GLAMOS says it has become increasingly common in recent years.
Sharp regional contrasts
Conditions vary across the Alps. Southeastern Switzerland has seen some of the worst snow deficits because of especially dry winter weather.
The Murtèl rock glacier and the Pers Glacier in the Engadine recorded snow depths 42% and 39% below the 2010-20 average respectively. The Rhone Glacier and the Great Aletsch Glacier were also in poor condition, with snow cover down by 26% and 32%.
By contrast, glaciers in the western Bernese Oberland and parts of Valais recorded snow depths closer to seasonal norms.
More on this:
GLAMOS article (in English)
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