What caused the Mississippi River flood of 2011?

The Mississippi River flood of 2011 was primarily caused by a combination of heavy rainfall and significant snowmelt during the late winter and early spring of 2011. These conditions, which included the Tornado Super Outbreak of 2011, caused the river's tributaries to swell, leading to a surge in the main channel of the Mississippi River throughout April and May.1

As the river rose, the U.S. Army Corps of Engineers utilized a system of levees and spillways to manage the flow and protect major settlements. In some instances, officials intentionally diverted water to prevent catastrophic flooding in populated areas, such as opening the Bonnet Carre Spillway and the Morganza Spillway to protect Baton Rouge and New Orleans. Despite these efforts, the flood submerged thousands of square miles of land and necessitated the evacuation of thousands of residents.1