Lake Assale, also written as Lake Asale or Lake Karum, in the Danakil Depression, was formed in the past when the area was periodically flooded by the Red Sea after which large amounts of marine salts deposits (120,000 ha) accumulated at what is now the lake. Covered with a thick salt crust, the area is part lake and part salt deposit.
Lake Assale is a former bay of the Red Sea, which from time to time got connected and disconnected and as it became disconnected the salts accumulated to layers of several hundreds of meters deep. On top of it is an extremely salty lake in many places covered by a thick crust that can support vehicles. The salt crusts vary from dark brown where mixed with soil to almost snow white in other places where it is purer.