Storm surge warning for Hamburg: Joshua” brings flood risk!

Storm surge warning for Hamburg: Joshua” brings flood risk!

The situation in northern Germany is currently tense. KATWARN has sounded the alarm in Hamburg because of the violent storm “Joshua”. There are warnings about a storm surge on the coasts; the water levels in Hamburg's Elbe area are said to be between 3.6 and 4.1 meters above normal. These warnings particularly affect low-lying areas such as the port, HafenCity and regions near the Elbe. Residents are urged to keep their vehicles safe to avoid damage. However, the mayor of Hallig Hooge, Michael Klisch, classified the weather situation as “nothing special” as Hooge is well protected by a summer dike. In contrast, other Halligen areas such as Oland are more frequently affected by floods.

The first effects of the storm were already noticeable when the fish auction hall in St. Pauli was flooded. In Hamburg-St. Pauli on Sunday, a water level of around 25 cm above the storm surge mark was measured, and no major incidents have been reported so far. Since Thursday, the storm “Joshua” has been causing wind speeds of up to 120 km/h, which has also had an impact on residents in the Stade district, where the alarm was triggered again via the Nina warning app. The Altes Land region in particular is at the focus of the flood risk, which has led to the closure of public green spaces in several cities such as Hildesheim and Hanover. Even weekly markets had to be canceled, and Lower Saxony's state forests warn against entering forests.

Storm surges and their historical significance

Storm surges are nothing unusual on the German coast. According to one definition, storm surges are “rises of water on the seashore caused by strong winds”. When water levels rise 1.5 meters above the mean high water level (MHW), it is a storm surge. If it is more than 3.5 meters above MHW, experts speak of a very severe storm surge. These phenomena occur primarily in spring and autumn on the North Sea coast.

The German Bight is one of the areas most at risk from storm surges in the world. Historically, storm surges had profound effects, changing coastlines in the Middle Ages and creating new bays such as the Jade Bay. Examples of previous devastating storm surges, such as the Marcellus floods and the Christmas flood of 1717, show how dangerous such natural events can be. The last major storm surge in Germany took place in 1962 and had devastating effects on coastal towns.

Precautions and recommendations

The authorities have taken numerous precautionary measures. The Federal Maritime and Hydrographic Agency expects water levels on the North Sea coast to be around 1.5 meters above mean high water. At the same time, the German Weather Service (DWD) is issuing warnings that there are leaf problems and recommending not to spend time outdoors. The ADAC has also published behavioral tips for drivers, advising them to avoid forest areas and reduce their speed in strong winds. This is happening against the background of increased return travel at the weekend, which is why forward planning is strongly recommended.

With these developments, it is to be hoped that the preparations will bear fruit and major damage can be avoided. Stay safe and heed the warnings from local authorities!