Storm surges in the Wadden Sea

Storm surges have hit the low-lying areas of the Wadden Sea at regular intervals throughout history. Extensive modern dyke construction has prevented fatalities for more than 100 years, but climate change may lead to new challenges for the Wadden Sea dykes.

The storm surge columns show how high the water has been during storm surges

Life with storm surges through time

In Denmark, we are no strangers to storms and storm surges. However, the Wadden Sea area has been particularly exposed due to its low-lying land. For the people who have lived on the Wadden Sea coast, the sea has always been a double-edged sword. On the one hand, the rich marshland and good sea connections to the outside world were very rewarding, but on the other hand, they had to live with the fact that storm surges periodically flooded their land, causing great destruction and even loss of life. However, technological developments and modern dikes have meant that it has been more than 100 years since a storm surge last claimed a human life in the Danish part of the Wadden Sea.

Wind, tides and air pressure

During a storm surge, the water level is much higher than normal. There are three factors that contribute to the occurrence of a storm surge. The first is wind buffeting, which occurs when the wind, for example from a storm, pushes the sea inland, causing the water to rise inland. The second is air pressure: low air pressure alone can cause the sea to rise by up to 40 cm. The third factor is the tide. In the Danish part of the Wadden Sea, the difference between high and low tide is about 1.5 metres - and if a storm coincides with high tide, the storm can be very violent.

Storm surges are increasing

The number of storm surges with water levels of two to three metres has more than tripled in the last four decades, while the Wadden Sea region has recently experienced the highest storm surges since 1634. The UN Intergovernmental Panel on Climate Change predicts that sea levels will rise over the next 100 years and that there will be more storms. As a result, dykes will come under greater pressure and cities along the Wadden Sea will once again face new challenges from storm surges.

Here you can experience the history of storm surges

Storm surge pillars have been erected in several places in the Wadden Sea National Park. These columns show how high the water has risen during storm surges over time. Visit the storm surge columns at:

  • Janderup Ladeplads
  • Ribe Skibbro
  • Mandø Forstrand
  • Mandø Ebbevej
  • Sønderho
  • Nordby
  • Marskmandshuset in Ballum Enge
  • Rømø Harbour
  • Vidå Slusen
  • Højer Gamle Sluse
Raised dykes that protect against storm surges.

Read more about storm surges in the Wadden Sea

Storm surge at the Wadden Sea can be a violent experience.

Fotos: Ulrik Pedersen og Jan Tandrup