Although far more rain is falling in Greece than in the Ahr Valley two years ago, the consequences have so far been less severe. This is due to several factors, explains an expert from the German Weather Service.
According to media meteorologist Markus Ubel, the amount of rain alone cannot be used to determine the strength of the effects. The damage caused by heavy rain depends on various factors. On the one hand, the previous history plays a role – for example whether it had rained a long time before and the soil was soaked. The type of soil is also important – the water seeps away better in sandy soil than in clay soil. The topography plays a decisive role – in the Ahr Valley all the water flowed into a single narrow valley and had nowhere to go.
During the Ahr Valley flood in July 2021, the amount of precipitation was between 100 and 200 millimeters per square meter. At least 134 people died then. On the other hand, rainfall of 754 millimeters per square meter was measured on Tuesday in the Greek town of Zagora, northeast of Volos. According to the weather agency EMY, this is more than has ever been measured in Greece. As of Wednesday, the known death toll was two.
Even if the DWD cannot say anything about the specific situation in Greece, the principle can also be seen in Germany: Shortly before the flood disaster in the Ahr Valley, almost the same amount of rain fell from the sky in the Uckermark (Brandenburg), said DWD expert Bösel. However, because the water was able to seep away easily in the shallow sandy soil, the effects there were much smaller.
