By the beginning of September, unusual heat had accelerated the melting of the Bernese glaciers. Since mid-September, there has been snow on the ice again.
Friday the 13th was a lucky day for the glaciers. On September 13th, snow fell in the Bernese Oberland in some areas below 1000 meters. Good for the ice and snowfields in the Oberland. A significant drop in temperature had already set in on September 9th. This meant that a lot of snow fell on the glaciers.
Snow white protects glacier ice
The snow’s white color is the perfect protection for the glacier ice underneath. It reflects sunlight and prevents it from thawing the ice. Snow also acts as a heat-insulating layer.
“The repeated snowfalls below the glacier tongues from mid-September onwards have led to a layer of snow more than one metre thick at higher altitudes such as the Jungfraujoch.” This is what glaciologist Andreas Bauder said when asked.
“It is unlikely that it will disappear again,” the glacier researcher and research associate at ETH Zurich is convinced. In 2023, things were very different: “A year ago, the warm weather and thus the melting of the glaciers lasted until mid-October.”
Before the early onset of winter in mid-September, things looked very different on the Bernese glaciers. The rainy last winter season had left behind a record-breaking blanket of snow at high altitudes . This initially gave glaciologists hope that the glaciers would lose little or no volume for once.
But things turned out differently . “The winter snow cover lasted for a relatively long time,” says Andreas Bauder. “But then it disappeared rapidly from mid-July onwards, and the glaciers in the Oberland and throughout Switzerland melted away in a short space of time, even at high altitudes.”
Zero degrees at 5000 meters
On the one hand, this is due to the high temperatures in July and August. August 2024 was the warmest August month ever recorded on the Jungfraujoch. Once again, the zero degree mark rose to over 5000 meters on an August day. And even at night, temperatures remained above zero at times, even at high altitudes.
The result: “From the warm second half of July and into August, the glacier ice melted practically day and night,” summarizes glaciologist Bauder. “The glacier streams carried large amounts of water.” And: “Never before has the loss of glacier mass been as pronounced in August as it has been this year.” This is what Matthias Huss, glaciologist at ETH Zurich, adds.
The losses are significantly higher than in August 2022 and 2023. Glaciers that extend far down are losing a particularly large amount of ice. “The glacier tongues are not just retreating,” says Huss, who also heads the Swiss glacier measuring network Glamos: “In some cases they are literally disintegrating.”
The Konkordiaplatz is located south of the Jungfraujoch. Glamos once again carried out spot measurements this year on the 900-meter-thick ice area at almost 2,700 meters above sea level, which marks the beginning of the Great Aletsch Glacier.
Almost 15 meters in 3 years
Result: The ice lost another 4 meters in thickness in the summer of 2024. In 2022 it lost 6 meters at this point and in 2023 4.7 meters. A loss of thickness of almost 15 meters in just 3 years. “We measure this across Switzerland with a network of gauge poles that are distributed across certain glaciers,” explains Matthias Huss.
In the Bernese Oberland itself, Glamos only measures the Plaine Morte. However, various adjacent glaciers are being observed, such as the Grosser Aletsch (Konkordiaplatz) and the Rhone Glacier.
Although the extent of glacier loss this year is not comparable to the extreme previous years of 2022 and 2023, in which a total of 10 percent of the ice volume of the Swiss glaciers disappeared, this year’s loss of 2.5 percent is still above the average of the last 10 years. At 2.6 percent, the loss on the Bernese glaciers is even slightly higher, according to Huss.
But how big is the glacier area and the volume of ice in the canton of Bern? “Good question,” answers the glaciologist: “We have never broken it down by canton.” Matthias Huss does know, however, that the Bernese Alps are second in Switzerland in terms of glacier area and volume after Valais. And he knows the data by catchment area.
30 km 2 glacier away
“If you combine the Aare and the Saane – which probably accounts for almost everything in the canton of Bern – I arrive at 10 cubic kilometers of glacier volume in 2016, the year of the last inventory, and around 7.8 cubic kilometers now.” According to Huss, the Bernese glacier area was around 170 square kilometers in 2016 and only 140 square kilometers now.
In other words: in just 8 years, almost a quarter of the volume and almost a fifth of the area of the Bernese glacier ice has disappeared. Matthias Huss calculates that this summer, 0.2 cubic kilometers of Bernese ice melted away. “So around 200 million tons or 200 billion liters of water.” 22 tons of melted ice for every person in Switzerland.
However, the very high temperatures from mid-July to early September and the lack of cooler breaks with snowfall at high altitudes were not the only factors responsible for the dramatic melting of glaciers this summer. The Saharan dust also played a decisive role.
Mauro Fischer is a lecturer and research associate in the Geomorphology, Natural Hazards and Risk Research group at the Geographical Institute of the University of Bern. He cites Saharan dust events in February, March and April last winter , which deposited fine dust on the snow-covered Bernese glaciers.
Sahara dust accelerates glacier melt
“Intensive Sahara dust deposits in the Bernese Oberland region occurred primarily at the end of March and beginning of April,” Fischer continued. “When the snow melted on the glaciers from the end of May/beginning of June, this dust increasingly accumulated on the old snow and firn surface.”
The accumulation of Saharan dust has accelerated the early summer snow melt on the glaciers. “This is because more solar energy is absorbed on darker surfaces than on lighter, dust-free old snow or firn,” explains Mauro Fischer.
“Unfortunately, in today’s climate, even record-high winter accumulation of snow on the Alpine glaciers is no guarantee of a balanced or even positive year in terms of the glacier mass balance.” This is what the scientist says at the end of the hydrological year, which runs from October 1 to September 30.
“It is impressive to witness what is happening right now,” says glaciologist Matthias Huss: “The speed of change is such that we could not have imagined until recently.” And: “Without the fresh snow from mid-September, the ice loss would have been even greater,” he emphasises.
“Glacier crevasses are getting bigger”
The operations managers at the Jungfraujoch High Alpine Research Station are also seeing the changes first hand. “The crevasses are getting bigger and more glaciers and rock falls are visible and audible,” says operations manager Erich Furrer. “The longer mountain and glacier tours go on, the more careful planning they need.”
“Get the right equipment, pay attention to the weather, book a mountain guide if necessary, respect closures,” says Furrer. “And sometimes give up or turn back!” In the future, we will have to live with the changes and phenomena mentioned: “Be it increased rockfall in the Alps, heavy rain, increased mudslides and rock falls.”