Tornadoes often cause a nationwide stir. The tornadoes in Germany are actually nothing special, as expert Thomas Sävert explains in the stern interview.

Note: This article was first published on October 1, 2021 and will be republished here due to the current weather conditions.

Mr. Sävert, according to the tornado list you maintain, there have already been 28 confirmed tornadoes, 14 plausible and 169 suspected cases this year. Is a tornado like the one in Kiel in Germany at the end of September nothing special?

no Actually, that’s nothing special. In this case, of course, when it occurs so spectacularly and causes damage and people are injured. In Kiel there were even two tornadoes, as can be seen on some videos. Luckily nobody died. But tornadoes are part of the weather in Germany, which many people are not aware of. This is already shown by the high number of confirmed and suspected cases mentioned above. They will also increase this year.

Can tornadoes be predicted?

There are two ways tornadoes form. One is very spontaneous in showers and thunderstorms. They usually don’t last that long, so you can hardly manage it. The situation is different when there are really heavy thunderstorms that exhibit rotations, so-called supercells. You can see them on radar images and then also say: The probability of a tornado developing is significantly higher here. If there is also a sighting, for example by a so-called “storm chaser” – which is mainly known in the USA, but there are also in Germany – then you can immediately issue a warning. This has also worked in Germany several times, but there are not that many storm chasers in this country.

In cases like the one in Kiel, things are looking rather bad.

What are the characteristics of a tornado? You know the characteristic tornadoes, is there more to it?

Wind pants and tornadoes are one and the same. In the USA they are also known as twisters, there is no difference, not even between tornadoes in Germany or the USA. It’s all the same physical phenomenon.

A tornado always occurs in connection with a shower or thunderstorm, with an updraft. A tornado is characterized by a small-scale vortex reaching from the cloud to the ground. But it doesn’t have to be visible all the time. A tornado is a vortex of air, and it’s initially invisible. At the top it becomes visible through condensation, i.e. cloud formation, then there is this funnel cloud. And below it becomes visible because something is being whirled up from below.

How strong can the storms in this country get?

Weak tornadoes have less than 118 kilometers per hour (km/h) wind speed, which would be the threshold for a hurricane. Strong tornadoes can certainly have speeds of up to 400 kilometers per hour or more – also in Germany, they are not only found in the USA. There is the internationally used Fujita scale, some may know it from the film Twister. For tornadoes, this ranges from F0 to F5. At F5 we are talking about wind speeds of more than 420 km/h, F1 starts at 118 km/h. In 1971 and 1973 we had two tornadoes in Kiel with a magnitude of F3 and wind speeds between 250 and 300 km/h. In Germany in 1979, we even had a tornado that tossed combine harvesters weighing tons through the air.

Do you know how strong the tornado in Kiel was?

With the tornado in Kiel, we are currently assuming that it was in the upper range of F1. F1 ranges from 118 km/h to a good 180 km/h. Of course, you can’t specify that exactly, you would need measurements for that. But you can say a lot based on the damage done. And the Fujita scale is based on the damage done. We last had a tornado in East Friesland this year (on August 16 in Großheide, editor’s note), which was already in the upper range of F2 based on the damage. And that’s wind speeds of around 250 kilometers per hour. That’s a different house number. The strength F1 occurs several times a year in Germany.

Are there any indications that there is a connection with climate change? Is it to be expected that the number of tornadoes in Germany will increase?

That’s difficult to answer. First, we need meaningful statistics. Since we have only been investigating tornadoes for 20 years and on a voluntary basis, our statistics are actually not yet sufficient. However, the 20 years show that the variability, i.e. the changeability, is extremely large from year to year. The number of confirmed tornadoes fluctuates extremely from year to year. So far there has been no trend at all. This means that we cannot yet say anything about whether there is a connection with climate change. Although there are studies that local storms can become more or stronger in the future, with the emphasis on can. However, whether this is also associated with tornadoes cannot be said in general terms. Because tornadoes are not only dependent on temperature, but also on a number of other factors. That’s why the question is not so easy to answer as I said.