Red alert

Thunderstorm mountains are nature’s “sharp weapon”

The cloud front as an unstable factor - the country still has a turbulent summer ahead of it.

(Bild: Krone KREATIV/Daniel Scharinger, Gerhard Bartel, BFKDO Waidhofen/Thaya)

Global warming is now making storms even more dangerous. The devastating hailstorm in the Waldviertel (Lower Austria) was just a harbinger of a turbulent summer. Nature is already charging ahead and preparing the next strike. Further millions in damage to agriculture and the like are imminent.

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

Nationwide, the months of February, March and spring as a whole were the warmest in the 258-year history of measurements. We also had the earliest hot day in Bruck an der Mur (Styria) on April 7, 2023. Whereas in the 1980s and 1990s there were just ten heatwave days - days with temperatures above 30 degrees - there are now 30 such days on average.

(Bild: Ö. Hagelversicherung)

The consequence of this global warming is that there is more energy and more water vapor in the atmosphere. This leads to more frequent and more intense extreme weather events such as frost, hail, storms, flooding and drought.

Agriculture, with its open-air workshops, is mainly affected. What does this mean for the farmers themselves? A large part of the harvest is often destroyed within minutes. No harvest, no yield - no yield means no income.

Millions in damage including a battle of words between experts
According to the Austrian hail insurance company, frost has already caused 56 million euros in damage this year and hail, storms and flooding 14 million euros. However, this does not even include the most recent natural disaster in the Waldviertel (Lower Austria). Agriculture in the districts of Gmünd, Waidhofen an der Thaya and Horn was damaged within a very short space of time. The damage has already been enormous in the past five years and is unlikely to improve any time soon.

Rapidly approaching heavy storms
In any case, the term "ghost thunderstorms" is already doing the rounds, describing local, fast-moving heavy thunderstorms. For Ubimet expert Nikolas Zimmermann, this is not the best word to use: "This phenomenon has always existed, in America they also talk about 'loaded gun' thunderstorms, I use the term 'lid-breaker cell': In such weather conditions, a stable layer in the atmosphere prevents air from rising - like the lid over a saucepan - which prevents the large-scale development of thunderstorms."

Hailstones the size of tennis balls destroyed an entire region in Lower Austria.

(Bild: BFKdo Waidhofen an der Thaya/St. Mayer)

The next storms are already approaching.

(Bild: Bartel Gerhard)

Dense showers also in Germany during the European Football Championship.

(Bild: EXPA/ Eibner/ Memmler)

The next storm is not long in coming
After a brief cool-down, summer is picking up speed again. Thunderstorms are once again on the weather radar and are likely to pose an increasing risk to property. Spring clouds are already growing on Saturday afternoon with the approach of a cold front in Vorarlberg and North Tyrol. Towards the evening, heavy showers are also possible in Salzburger Land, Upper Austria, Upper Styria and western Lower Austria. Included: hailstones up to 4 centimetres in diameter and squalls. Nature is loading up her weapon!

"Rain less frequent, but all the stronger"
Weather expert Nikolas Zimmermann from Ubimet assesses the current storm situation in an interview with "Krone":

"Krone":Rainfall has been shorter and more concentrated for some time now. What is the reason for this?
Zimmermann: Global warming is intensifying the water cycle: on the one hand, more water is evaporating, on the other hand, rainfall is becoming heavier. For every degree of warming, the atmosphere can absorb around 7 percent more water vapor. However, the evaporation rate only increases by around 4 percent, which means that evaporation cannot keep up with the increased absorption capacity of the atmosphere. This imbalance means that it tends to rain a little less frequently, but when the weather conditions are right, it rains all the more heavily.

Zimmermann and his colleagues at the local Ubimet are also analyzing the recent storms in the country.

(Bild: Ubimet)

Is the total amount of precipitation increasing or decreasing throughout the year?
There is currently no significant trend towards more or less precipitation in Austria. In some regions in the lowlands away from the mountains, it is tending to get a little drier, while in the Alps it tends to get a little wetter. However, this is overlaid by larger, sometimes multi-year fluctuations. In 2022, for example, drought was still a huge issue throughout Central Europe, but since 2023 it has suddenly been wetter than average in many regions.

Is it hailing more often this year?
There are regional differences in hail worldwide, with areas where the risk of hail is increasing and areas where it is decreasing. For Central Europe, however, new studies clearly indicate an increase, with a strong trend towards more frequent damage events, especially in northern Italy. Of course, this does not necessarily mean that hail is more frequent, but that any hail is much larger.