St. Lucia’s flood was a storm tide that affected the Netherlands and Northern Germany on this day in 1287 (the day after St. Lucia Day) when a dike broke during a storm, killing approximately 50,000 to 80,000 people in the sixth largest flood in recorded history.
Much land was permanently flooded in what is now the Waddenzee and IJsselmeer. It especially affected the north of the Netherlands, particularly Friesland. The island of Griend was almost destroyed, only ten houses being left standing. The name Zuiderzee dates from this event, as the water had merely been a shallow inland lake when the first dikes were being built, but rising North Sea levels created the “Southern Sea” when floods including this flood came in.