I attended a briefing hosted by the NOLA District, USACE. The colonel said their models indicate that this flood will exceed the 1973 flood by quite a bit. That was the flood that nearly changed the course of the Mississippi River and a complete re-engineering of the lower MS management system. Col also said that this one could rival or even exceed 1927 flood.

The 1927 flood extended from lower Illinois to New Orleans and from half-way across the state of Mississippi to half-way across the state of Louisiana. The 1927 flood is why we have Chicago blues -- the flood caused the largest single-event migration of Americans in history.