Three tornadoes passed through Germany on Friday. They left a trail of destruction, leaving dozens of wounded. What is the devastating weather phenomenon in the middle of Europe? We asked SRF Meteo.
Sina Lenggenhager
Weather SRF
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Sina Lenggenhager has been part of the Meteo team since summer 2019. After studying in Basel and Bern, she defended her doctorate in climate sciences in 2018.
SRF Meteo, we are quite experienced with our assessments, but we usually locate tornadoes in the US. What is this weather phenomenon in the middle of Europe doing?
Sina Lenggenhager: Tornadoes are most common in the US, with 1,000 to 2,000 tornadoes each year. This is because the cold air from Alaska is free to meet the moist, warm air from the Gulf of Mexico in the open plains. At these extreme limits of air masses, severe thunderstorms quickly form and tornadoes can develop in it. In Europe, the Alps make it difficult to meet such different masses of air.
In theory, can there also be tornadoes in Switzerland?
Yes, tornadoes also happen here. However, they are usually weaker than in the US. A particularly powerful tornado passed through the Vallée de Joux in Vaud on August 26, 1971, causing extensive damage on a 23-kilometer swath.
What conditions are needed for the formation of tornadoes?
As already mentioned briefly, they are formed at the interface of very different air masses. In addition, there must be enough moisture for powerful storm clouds to form. Another condition is the so-called wind shear, which is a strong change in the direction and / or speed of the wind at altitude.
What distinguishes a tornado from a wind or water hose as we know it here?
Both the terms “tornado” and “windscreen” refer to the same weather phenomenon. When a tornado forms over water, it is sometimes called a “water tornado”.
What does climate change have to do with it? Or to put it another way: will we have to expect tornadoes more in the future?
It is still uncertain how or if climate change will affect the frequency of tornadoes. Basically, due to global warming, there is more energy in the atmosphere and therefore more possibilities for extreme events to occur. Therefore, theoretically, it is possible to imagine that stronger tornadoes will occur in the future.
Legend: Rubble and damaged cars after the Paderborn storms (May 21, 2022). key stone