On May 3 , 1849 , a Mississippi River levee breach upriver from the city ( around modern River Ridge , Louisiana ) created the worst flooding the city had ever seen . The flood , known as at Sauvé 's Crevasse , left 12,000 people homeless . While New Orleans has experienced numerous floods large and small in its history , the flood of 1849 was of a more disastrous scale than any save the flooding after Hurricane Katrina in 2005 . New Orleans has not experienced flooding from the Mississippi River since Sauvé 's Crevasse , although it came dangerously close during the Great Mississippi Flood of 1927
Great Mississippi Flood of 1927
Great Mississippi Flood of 1927
History of New Orleans