For residents living on the coast, the sea has always been a double edged sword. On the one hand they have benefited from the rich soil of the salt marshes and from the seaways connecting to the rest of the world. On the other hand, they have had to live with storm surges that regularly flooded their lands, destroyed their property and even cost lives. Technological advances have made it possible to build bigger and more efficient dykes. Even though storm surges in the Wadden Sea have become more frequent over the past few decades, it has been more than a century since there were any fatalities.
Wind, tidal waters and atmospheric pressure
The word ‘storm surge’ refers to water levels that are much higher than normal. Three factors can contribute to the occurrence of a storm surge. The first is wind stresses. This is when wind, possibly from a storm, pushes the sea towards land, which causes water to amass and to rise along the coast. The second factor is atmospheric pressure. Low atmospheric pressure in itself can cause the sea to rise by up to 40 cm. The third factor is tidal waters. There is a 1.5-metre difference between low tide and high tide in the Wadden Sea. Therefore, the severity of the storm surge depends on whether the storm coincides with high tide. The hurricane in December 1999 hit the Wadden Sea at low tide. So, even though it was probably the worst storm to hit the area in hundreds of years, the storm surge did not flood the dykes by Ribemarsken.
The Great Drowning
The Wadden Sea has been hit by many violent and destructive storm surges over time.