Mount Sonnblick is a 3,106-meter (10,190-foot) high mountain in the Austrian Alps. It averages more than 20 meters (66 feet) of snow a year. Close to the peak, it takes most of summer for that to melt. Except for this year, that is, when the Mount Sonnblick Observatory is reporting a record like few others. 

Not only has this year's snow thawed earlier than ever before, but it's also broken the previous record by more than a month. In athletics terms, that's a bit like someone running a three-minute mile, or a marathon in 90 minutes. And just as with sporting aberrations like those, it's clear it didn't happen naturally.

The Mount Sonnblick Observatory was built in 1886, following a meteorologic society conference that decided we didn't know enough about high-altitude atmospheric conditions. The location was deemed to be one of the few really accessible sites in Europe over 3,000 meters (9,840 feet), and the fact a nearby village was an early pioneer of electricity didn't hurt. It's been carefully recording data ever since, today supplemented with cameras connected to the Internet.

The existence of a reliable record of temperature, precipitation, and snowmelt over such a long period, the longest in the world at such high altitude, has proven invaluable for climatologists. So it was quite a shock when the Twitter account Extreme Temperatures Around The World alerted people elsewhere to what the Observatory's scientists already knew.

Snow thickness at the measuring station got down to about 3 centimeters (1 inch) overnight before experiencing a small rebound. However, as temperatures rose with the Sun, the remnant snow became so thin, despite heavy cloud cover, the sensor started spitting out near-random values.

Before this year, the lowest snowpack ever recorded at Sonnblick in June was 120 centimeters (47 inches), with an average of 307 centimeters (121 inches) at the end of the month. This year it reached 39 centimeters (15 inches).

The timing of the thaw is affected not just by summer temperatures, but also by the depth of winter snow. Even factors like the amount of dust arriving from the Sahara play a part. Nevertheless, beating the previous record by almost 40 days is certainly not something that could have occurred under pre-Industrial climatic conditions, at least not in the last few million years.

Europe as a whole has been experiencing a very hot summer, with June close to the hottest ever recorded in many countries. Resulting lowland deaths from heatstroke are hard to track, but in the Italian Alps the tragedy has been more visible and dramatic, with a sudden glacier collapse killing at least six people two days ago.

Three days earlier Dr Giovanni Baccolo and Lander Van Tricht of the European Geophysical Union explained why 2022 was a perfect storm for Alpine glaciers. They note the melting is so extreme that “there is a risk that the graphs showing glacier balances will have to be rescaled.” All across the Alps snow is melting one to two months earlier than normal. 

Most of the great rivers of Europe are fed by Alpine snowmelt through the summer and autumn. This year could see some of them run very low indeed if autumn rains are not unusually heavy.

It's not just Europe of course. This year, like every year recently, has been marked by a series of record-breaking heat events from one pole to another and in some of the most populated places on Earth.