A huge storm and associated storm tide in the North Sea and English Channel on 14 December 1287 , known as St. Lucia's flood in the Netherlands, kills thousands and reshapes the coastline of the Netherlands and England.
In the Netherlands, a fringing barrier between the North Sea and a shallow lake collapses, causing the fifth largest flood in recorded history which creates the Zuider Zee inlet and kills over 50,000 people; it also gives sea access to Amsterdam, allowing its development as an important port city.
In England, parts of Norfolk are flooded; the port of Dunwich in Suffolk is further devastated; and in The Fens through the vehemence of the wind and the violence of the sea, the monastery of Spalding and many churches are overthrown and destroyed "All the whole country in the parts of Holland was for the most part turned into a standing pool so that an intolerable multitude of men, women and children were overwhelmed with the water, especially in the town of Boston, a great part thereof was destroyed."
In Germany the Chronicles speak of 50.000 killed and total destruction. Many villages disappeared forever. In the current district of East-Frisia alone thirty villages disappeared in the North Sea. Also a first stage of the Dollart came into existence. Because of the large loss of land and the relative insecurity of living in the now far more unprotected peatlands (remember that natural barriers had been removed by the flood) many survivors gave up their ways of living in the fertile peatlands and moved to the Geest.