The February flood of 1825, also known in Germany as the Great Hallig Flood (Große Halligflut), was a devastating flood that occurred from 3 to 5 February 1825 on the North Sea coast in which about 800 people were drowned. Particularly affected was the North Sea coast of Jutland, Slesvig and Germany. The sand spit Agger Tange was broken through, and the Limfjord got its western opening to the sea. Henceforth, North Jutland has been an island.