Watch The Great Flood (2012) : Full Movie Online Free The Mississippi River Flood of 1927 was the most destructive river flood in American history. In the spring of 1927, the river broke out of its banks in 145 places and inundated 27,000 square miles to a depth of up to 30 feet. Part of it enduring legacy was the mass exodus of displaced sharecroppers. Musically, the Great Migration of rural southern blacks to Northern cities saw the Delta Blues electrified and reinterpreted as the Chicago Blues, Rhythm and Blues, and Rock and Roll. Using minimal text and no spoken dialog, filmmaker Bill Morrison and composer - guitarist Bill Frisell have created a powerful portrait of a seminal moment in American history through a collection of silent images matched to a searing original soundtrack.