100 populated locations were experiencing major or moderate flooding on May 8, 2011.
Source: National Weather Service |
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Date | May 4, 2011 to June 20, 2011 |
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Location | Mississippi River Valley, United States |
Deaths | About 20, beyond 392 in preceding storms |
Property damage | US$2 to 4 billion |
The Mississippi River floods in April and May 2011 were among the largest and most damaging recorded along the U.S. waterway in the past century, comparable in extent to the major floods of 1927 and 1993. In April 2011, two major storm systems deposited record levels of rainfall on the Mississippi River watershed. When that additional water combined with the springtime snowmelt, the river and many of its tributaries began to swell to record levels by the beginning of May. Areas along the Mississippi itself experiencing flooding included Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. U.S. President Barack Obama declared the western counties of Kentucky, Tennessee, and Mississippi federal disaster areas. For the first time in 37 years, the Morganza Spillway was opened on May 14, deliberately flooding 4,600 square miles (12,000 km2) of rural Louisiana to save most of Baton Rouge and New Orleans.
Fourteen people were killed in Arkansas, with 392 killed across seven states in the preceding storms. Thousands of homes were ordered evacuated, including over 1,300 in Memphis, Tennessee, and more than 24,500 in Louisiana and Mississippi, though some people disregarded mandatory evacuation orders. The flood crested in Memphis on May 10 and artificially crested in southern Louisiana on May 15, a week earlier than it would have if spillways had not been opened. The United States Army Corps of Engineers stated that an area in Louisiana between Simmesport and Baton Rouge was expected to be inundated with 20–30 feet (6.1–9.1 m) of water. Baton Rouge, New Orleans, and many other river towns were threatened, but officials stressed that they should be able to avoid catastrophic flooding.