Time and time again, people are reminded that the weather and the sea are unpredictable. A very special natural phenomenon in this context is the so-called “Kreuzsee” – waves that form in such a way that they form a kind of checkerboard pattern on the water and look like giant squares. TRAVELBOOK asked an expert: How does the Kreuzsee develop – and how dangerous is it?
Dr. Ralf Weisse from Helmholtz Center Geesthacht for materials and coastal research explains: “Waves move in different directions on the water, depending on how the wind blows. The Kreuzsee is created when the wind changes its direction, for example when pulling one Cold weather front. Then, due to the change of direction, quasi ’new’ waves meet old ones that have already been created. ”These opposite movements would then lead to the formation of the cross waves. The following also applies: the stronger the wind, the higher the waves. “However, the fact that the waves take the form of a checkerboard pattern is a special case – it can occur if they hit an obstacle and thereby change their direction. Cross waves usually show a chaotic pattern.
Danger to ships and swimmers
This mood of nature is dangerous for ships: “Captains usually try to approach waves at a small angle, because coming from the side are more dangerous for the stability of the ship. But if they now come from different directions, it is of course more difficult to adjust to them and correctly assess a potential danger. ”Cross waves are a serious factor that is also responsible for ship accidents. In the vicinity of the beach, however, the Kreuzsee poses no danger, since all waves would automatically align themselves towards the coast. However, you should definitely avoid swimming at Kreuzsee, because this would create strong currents against which even experienced swimmers would have no chance.
Incidentally, according to Weisse, the Kreuzsee is a phenomenon that occurs quite regularly and occurs differently depending on the region – in the North Sea, for example, with a higher frequency because cold fronts often pull through here. There are also cross waves on the Atlantic: “We are even observing that storms from other regions can bring in new waves that then contribute to the creation of cross waves. For example, surfers in Hawaii sometimes ride waves caused by storms thousands of kilometers away. ”