Storm tides of the North Sea are coastal floods associated with extratropical cyclones crossing over the North Sea, the severity of which is affected by the shallowness of the sea and the orientation of the shoreline relative to the storm's path, as well as the timing of tides. The water level can rise to more than 5 metres (17 ft) above the normal tide as a result of storm tides. Northern Germany and Denmark are particularly susceptible to storm tides. The coastline of the German Bight forms an L-shape facing northwest. Also vulnerable are the United Kingdom and the Netherlands, where the sea shallows and is funnelled toward the English Channel. Storm tides are a regular occurrence in the North Sea basin; several form each year. Although most do not cause significant damage, the impact of some has been devastating. During one, the February flood of 1825, the Danish coastline changed, as the North Jutlandic Island became separated from the Jutland Peninsula.

Major storm tides

Recent storm tides

The flood of 1976 and the "North Frisian Flood" of 1981 brought the highest water levels measured to date on the North Sea coast, but because of sea defences such as improved warning systems and dikes built and modified after the flood of 1962, these led only to property damage.

Comparative table of surge heights along the east coast of Britain