The Burchardi flood (also known as the second Grote Mandrenke) was a storm tide that struck the North Sea coast of North Frisia and Dithmarschen (in modern-day Germany) on the night between 11 and 12 October 1634. Overrunning dikes, it shattered the coastline and caused thousands of deaths (8,000 to 15,000 people drowned) and catastrophic material damage. Much of the island of Strand washed away, forming the islands Nordstrand, Pellworm and several halligen.