The snow at the highest observatory in the world to be operated all-year-round is expected to completely melt in the next few days, the earliest time on record.
Scientists at the Sonnblick observatory in the Austrian Central Alps, which is 3,106 metres (10,190ft) above sea level, have been shocked and dismayed to see the snow depleting so quickly.
Some years the peak is covered in snow all summer. But this year it has melted more than a month before the previous record time, which was 13 August in 1963 and 2003.
Alexander Orlik, a climatologist at the Zentralanstalt für Meteorologie und Geodynamik, said: “The snow depth today was 3cm. I expect it to be completely gone by today or the day after. It is not usual for the snow to melt completely down. In some years the snow cover is there the whole summer. But the earliest it has before is August.”
Throughout June, snow has been at the lowest levels since records began in 1938.
Orlik said: “On 30 June, the snow depth on Sonnblick was 39cm. The previous lowest snow depth in June was 120cm, in 1942. In an average June there is 307cm of snow at the end of the month. Last year in June, the minimum snow depth was 362cm.”
The observatory publishes the snow level every 10 minutes, along with other data. Rainfall affects the measurements. But the steady downwards trend is clear to see, and as of Tuesday the snow was down to just a couple of centimetres.
Sonnblick was built in 1886, for scientists to explore the higher levels of the atmosphere. Since then it has been used by meteorologists to forecast the weather, and hosts the mountain observatory with the longest and most reliable climatic data.
The heating climate in Europe, where there have been scorching heatwaves, has caused much of the snow and ice on the mountains to melt unusually quickly.
This had a tragic outcome this week at the Marmolada mountain in Italy, where at least seven people died after a glacier collapsed, causing an avalanche. Scientists linked the disaster to the climate crisis, as the ice has become weakened due to sustained heat.