St. Lucia's flood (Sint-Luciavloed) was a storm tide that affected the Netherlands and Northern Germany on 13/14 December 1287 (OS), St. Lucia Day and the day after, killing approximately 50,000 to 80,000 people in one of the largest floods in recorded history. A low-pressure system mixed with a high tide caused the North Sea to rise over the seawalls and dikes, causing a large portion of the Netherlands and Northern Germany to be flooded.

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.