In the Baltic Sea region, more than 50 million people live in coastal areas which can be flooded during intense storms. The most dangerous events are a combination of circumstances, such as high waves pushing water on the coast and, at the same time, raised water level caused by other factors. For example, in January 2005, the devastating windstorm Gudrun (Erwin in the German weather service terminology) struck the Baltic Sea countries. It caused coastal flooding and widespread damage to infrastructure and forests killing 17 people (one in Estonia). The damage caused by this storm was due to a combination of multiple factors, such as prolonged winds from a particular wind direction in the North Sea (pushing the water from the North Sea to the Baltic Sea), lack of protecting ice cover and extreme wave heights. The storm Gudrun confirms that a combination of factors can be hazardous.

    The paper “Coastal flooding: Joint probability of extreme water levels and waves along the Baltic Sea coast” by Dr. Nadezhda Kudryavtseva, Dr. Andrus Räämet and Dr. Tarmo Soomere was published in the Journal of Coastal Research last week. In this paper, the team of scientists from Tallinn University of Technology demonstrate that the combination of two factors, high waves and high water levels can appear at the same time rather often in the Sea of Bothnia, which is located between Sweden and Finland. Therefore, drastically increasing the risk of flooding in those areas. The analysis is based on the wave model results performed on the Taltech HPC cluster. Interestingly, the Gulf of Finland have lower chances of extreme flooding than in the Sea of Bothnia, but higher than along the Lithuanian, Polish, and German coastlines. This work shows the importance of a better understanding of joint events in the Baltic Sea. It raises a question if triple or even quadruple events can cause even more dangerous floods in the Baltic Sea?

The paper “Coastal flooding: Joint probability of extreme water levels and waves along the Baltic Sea coast” by N. Kudryavtseva, A. Räämet, T. Soomere is published May 26th in Journal of Coastal Research, 95 (Sp1), 1146 – 1151, 2020, https://doi.org/10.2112/SI95-222.1

Dr. N. Kudryavtseva is a Senior Research Scientist working since 2015 in the Laboratory of Wave engineering, Department of Cybernetics, Tallinn University of Technology, Akadeemia 21,12618 Tallinn, Estonia, nadezhda.kudryavtseva@taltech.ee, https://www.researchgate.net/profile/Nadia_Kudryavtseva