Warning signal: thunderstorms are nature’s “sharp weapon”.

There have always been heat waves, thunderstorms with heavy rain, hail, floods and mudslides. But the potential effects have become more intense. The fact is: climate change, that is, global warming caused by the burning of fossil fuels, is noticeable. 2023 alone was the warmest year ever recorded.

Nationally, the months of February, March and spring were generally the warmest in the 258-year history of measurements. The earliest warm day in Bruck an der Mur (Styria) was also on April 7, 2023. While only ten warm days – i.e. days with temperatures above 30 degrees – were recorded in the 1980s and 1990s, there are now an average of thirty such days.

The result of this global warming is that there is more energy and more water vapour in the atmosphere. This leads to more frequent and more intense extreme weather conditions such as frost, hail, storms, floods or droughts.

The main affected area is agriculture with its open-air workshops. What does this mean for the farmers themselves? Often a large part of the harvest is destroyed within minutes. No harvest, no yield – no yield means no income.

Millions in damage, including a war of words between the experts
According to the Austrian hail insurance, there has already been 56 million euros in damage from frost this year and 14 million euros from hail, storms and floods. The most recent natural disaster in the Waldviertel (Lower Austria) has not yet been taken into account. Within a very short time, agriculture in the districts of Gmünd, Waidhofen an der Thaya and Horn was damaged. The damage has already been enormous over the past five years and it is unlikely that there will be any improvement in the short term.

Fast approaching severe thunderstorms
In any case, the term ‘ghost thunderstorm’ is now doing the rounds; it describes local, rapidly approaching heavy thunderstorms. For Ubimet expert Nikolas Zimmermann, it is not the best word creation: “This phenomenon has always existed; in America they also speak of ‘loaded gun’ thunderstorms, I use the term ‘lid breaker cell’: in such weather conditions a stable layer is created prevents “The atmosphere makes air rise – like the lid of a cooking pot – which prevents large-scale thunderstorms.”

The next storm won’t be long in coming
After a brief cooling, summer is getting underway again. Thunderstorms are back on the weather radar and will likely bring increasing danger to property. Cumulus clouds are already growing on Saturday afternoon as a cold front approaches Vorarlberg and North Tyrol. Towards evening, heavy showers are also possible in Salzburger Land, Upper Austria, Upper Styria and western Lower Austria. Also in the bag: hailstones up to 4 centimetres in diameter and showers. Nature is loading her weapon!

“Rain less frequent, but stronger”
Weather expert Nikolas Zimmermann from Ubimet classifies current events in terms of severe weather in an interview with “Krone”:

“Crown”:The rainfall has been shorter and more concentrated for quite some time. What is the cause of this?
Zimmerman: As a result of global warming, the water cycle intensifies: on the one hand, more water evaporates and, on the other hand, rain falls more heavily. For every degree of warming, the atmosphere can hold about 7 percent more water vapor. However, the evaporation rate only increases by about 4 percent, which means that evaporation cannot keep up with the increased absorption capacity of the atmosphere. This imbalance causes it to rain slightly less often, but even more heavily when the weather conditions are good.

Does the total amount of precipitation increase or decrease during the year?
There is currently no significant trend towards more or less precipitation in Austria. In some regions in the lowlands, far away from the mountains, it is usually somewhat drier, while in the Alps it is usually somewhat wetter. However, this is overshadowed by larger fluctuations, some of which last several years. For example, in 2022 drought was a major problem in Central Europe, but since 2023 it has suddenly been above average wet in many regions.

Are you in a rush this year?
When it comes to hail, there are regional differences around the world, so there are areas where the risk of hail is increasing and areas where it is decreasing. However, new research clearly shows that there is a strong trend towards more frequent damage events in Central Europe, especially in Northern Italy. Of course, this does not necessarily mean that hail is happening more often, but rather that when it does occur, it will be much bigger.