Fishing Vessel In The Rough Waves, North Sea

Storm tides threaten, in particular, the coasts of the Netherlands, Belgium, Germany, and Denmark and low lying areas of eastern England particularly around The Wash and Fens. Storm surges are caused by changes in barometric pressure combined with strong wind created wave action.
The first recorded storm tide flood was the Julianenflut, on 17 February 1164. In its wake the Jadebusen, (a bay on the coast of Germany), began to form. A storm tide in 1228 is recorded to have killed more than 100,000 people. In 1362, the Second Marcellus Flood, also known as the Grote Manndränke, hit the entire southern coast of the North Sea. Chronicles of the time again record more than 100,000 deaths as large parts of the coast were lost permanently to the sea, including the now legendary lost city of Rungholt. In the 20th century, the North Sea flood of 1953 flooded several nations' coasts and cost more than 2,000 lives. 315 citizens of Hamburg died in the North Sea flood of 1962.
- Tsunamis
Though rare, the North Sea has been the site of a number of historically documented tsunamis. The Storegga Slides were a series of underwater landslides, in which a piece of the Norwegian continental shelf slid into the Norwegian Sea. The immense landslips occurred between 8150 BC and 6000 BC, and caused a tsunami up to 20 metres (66 ft) high that swept through the North Sea, having the greatest effect on Scotland and the Faeroe Islands. The Dover Straits earthquake of 1580 is among the first recorded earthquakes in the North Sea measuring between 5.6 and 5.9 on the Richter Scale. This event caused extensive damage in Calais both through its tremors and possibly triggered a tsunami, though this has never been confirmed. The theory is a vast underwater landslide in the English Channel was triggered by the earthquake, which in turn caused a tsunami. The tsunami triggered by the 1755 Lisbon Earthquake reached Holland, although the waves had lost their destructive power. The largest earthquake ever recorded in the United Kingdom was the 1931 Dogger Bank earthquake, which measured 6.1 on the Richter Scale and caused a small tsunami that flooded parts of the British coast.