Bonn/region After several thunderstorms over Bonn and the region at the weekend, the weather remains unsettled at the beginning of the week. The GA explains why there are currently thunderstorms in Bonn and the region and how to behave during thunderstorms.
The German Weather Service (DWD) warned on Monday again of showery rain, but also of isolated thunderstorms with heavy rain and hail. Already at the weekend on Saturday night, the sky unloaded after the heat of the past days with thunderstorms and heavy rain over Bonn and the region. In the Rhine-Sieg district alone, the fire department was called out on 130 occasions. At Bonn's main train station, the storm caused a power outage.
The storm at the weekend was typical for this time of year, says Bonn weather expert Dr. Karsten Brandt of Donnerwetter.de GmbH. The air had heated up extremely in the past days. The much cooler air from the Atlantic then penetrated the subtropical air and caused the strong thunderstorm to develop. "This is not unique to us, but is a Central European phenomenon normally seen in late May, early June," Brandt said. The large temperature difference between the subtropical and Atlantic air, a lot of moisture and also the time of day when the thunderstorm unloads are decisive for its strength. If it discharges toward afternoon or evening, as it did over the weekend, it is usually much stronger than in the morning, he said.
"The thunderstorm Sunday night was spectacular. It was very lightning-rich, and the amount of rain varied greatly between regions," Brandt said. While 10 to 15 liters per square meter fell west of the Rhine in the region and in the Eifel, it was 25 liters in Bonn and 80 to 90 liters along the line from the Siebengebirge to Much.
For the coming days, Brandt said it is unlikely that there will be such a strong thunderstorm again. "The air has cooled down and will also remain cool until about Thursday. It won't get warmer again until the weekend, when thunderstorms may return." By the end of July, strong thunderstorms are typical, the weather expert said, because that's when solar radiation is highest because of the length of the days. And the more the air warms, the higher the risk of thunderstorms, he said.
More than two million lightning strikes are registered in Germany every year, according to the German Weather Service (DWD). Most of them are so-called cloud lightning, which poses no danger. Ground lightning, on the other hand, which - as the name suggests - comes from the clouds and strikes the earth, and between 200,000 and 400,000 of these occur every year. After all, a lightning strike can reach an amperage of up to 40,000 amperes.
Here's how to behave during thunderstorm when you’re outdoors
"Oaks you shall leave, beeches you shall seek" - this is an old folk saying about protection against thunderstorms. However, this should not be followed. Trees always pose a potential danger, as lightning usually strikes the highest point in the area - no matter what kind of tree it is. Therefore, one should stay away from tall trees as well as from poles or the like.
Lying flat on the ground does not help either. A lying person offers little elevation, but a lot of attack surface. It is better to make yourself as small as possible: Feet together, squat down and embrace the legs. If you have a bicycle with you, it is also better to park it and seek shelter a little away from it, as the metal of the frame can also have an attracting(ve) effect.
If you are surprised by a storm while swimming, get out of the water! Lakes, open-air swimming pools and other bodies of water are particularly dangerous when a thunderstorm starts, as water is a particularly good conductor of electricity.
How to behave in buildings during thunderstorms
Basically, you are safe in solid buildings. However, since there is no lightning conductor obligation for residential buildings in Germany, there are also some things to keep in mind. In houses without lightning protection, electrical devices should be switched off or, even better, disconnected from the power supply, as they break easily. If you want to be on the safe side and still continue to use your devices, you can install a surge protector directly on the plug. Mobile electrical parts can, of course, continue to operate without this fuse. However, one should not forget that next to the handset there is also a telephone base or a router, which in turn are directly connected to the power and are therefore more at risk.
How to behave during a thunderstorm in a car, train or plane
Cars, buses and trains offer protection against thunderstorms because they form a Faraday cage. Since they are made of metal, just like airplanes, they conduct the energy of lightning - but not inward. As long as the windows are closed, nothing can happen here.
Original text: (ga)
Translation: Mareike Graepel