Swiss glaciers, which lost 10 per cent of their volume in 2022 and 2023 alone, had little snow cover at the end of winter this year, according a report.
The depth of snow on them was 13 per cent lower than the average of 2010-2020, showed data analysed by the Glacier Monitoring Switzerland (Glamos).
This is an alarming sign, indicating their vulnerability to global warming. Every winter, as temperature drops, the glaciers receive snowfall. This helps them replenish the snow cover lost during summer.
Once winter ends and temperatures begin to soar again, the snow cover protects glaciers from heat and sunlight. A low cover exposes them to more rapid melting during summer, pushing glaciers to extinction and leading to global sea-level rise.
This year's below-average snow cover was despite heavy snowing during 2024, the Glamos team observed. The deficit, however, was still less severe than in 2022 and 2023, which were dry years.
Yet, the extent of snow cover right now indicates "another difficult year for glaciers", said Matthias Huss, who leads Glamos.
Matthias's team studies snow depth on Swiss glaciers every year. This year, they found 1-4 metres thick snow on the 21 glaciers they surveyed.
The team extrapolated the findings to all the 1,400 glaciers in the region and observed a “winter snow deficit” of 13 per cent compared to the 2010-2020 average, the report noted.
The thickness varied varied according to region: Glaciers in northeastern Switzerland were left with very low snow cover, but the south and southwest areas retained near-average levels due to substantial snowfall in mid-April, the data showed.
Last summer, despite good snowfall, Swiss glaciers lost 2.4 per cent of their volume to the hot summer. The retreat, the authors highlighted in the report, was aided by deposition of dust from the Sahara Desert.
This is because layers of dust on glacial snow reduces the albedo effect (sunlight and heat reflecting capacity) of glaciers. Dust-free surfaces are whiter and are able to reflect more.