Great Mississippi Flood of 1927: America's Worst River Flood

The Great Mississippi Flood of 1927 was the most destructive river flood in United States history. From April to August 1927, the swollen Mississippi River and its tributaries broke through levees across the lower valley, flooding some 27,000 square miles (about 70,000 sq km) and driving hundreds of thousands of people from their homes. Its handling exposed deep racial injustices in the American South and led Congress to make flood control a national responsibility.

Background

For decades the policy on the lower Mississippi had been “levees only”: the belief that high embankments along the river would keep floods out and scour the channel deeper. Local levee boards and the US Army Corps of Engineers built thousands of miles of levees, but there were few outlets or spillways to release water during extreme floods. The Mississippi River Commission, created by Congress in 1879, supervised much of this work, and engineers repeatedly assured the public that the levees were strong enough to contain any flood.

Heavy rains fell across the Mississippi basin from the summer of 1926 onward. By the end of the year rivers such as the Cumberland and Tennessee were already in flood. In early 1927 further storms struck the Midwest and South, and by spring vast volumes of water were moving down the Mississippi and its tributaries, including the Missouri, Ohio, Arkansas and White Rivers.

The flood

Levees began to fail in April 1927. The most important break occurred on 21 April at Mounds Landing, north of Greenville, Mississippi, where a huge crevasse released a torrent of water into the Mississippi Delta. Within days much of the Delta was under water, in places to a depth of several metres, and Greenville itself was flooded for weeks.

Breaks in Arkansas, Louisiana and other states followed. In total, the waters covered parts of seven states, and in some areas the land stayed flooded for months. Railways, roads, farms and towns were submerged, and the spring planting season was lost across much of the region.

As the crest moved south, New Orleans’ business leaders feared that the city would be flooded. On 29 April, with state and federal approval, engineers dynamited the levee at Caernarvon, below the city, to relieve pressure on the river. The released water flooded much of St. Bernard and Plaquemines parishes. The river crest later proved lower than feared because of upstream breaks, and the affected residents, many of them trappers and fishermen, received very little of the compensation they had been promised.

Relief and Herbert Hoover

President Calvin Coolidge appointed Secretary of Commerce Herbert Hoover to lead a special relief committee working with the American Red Cross. Hoover organised boats, supplies and more than 150 refugee camps. His energetic management drew national praise and greatly increased his popularity.

Coolidge himself did not visit the flooded region, which attracted criticism. The relief effort was funded mainly by private donations and the Red Cross rather than direct federal aid, reflecting the limited role of the national government at the time. The Red Cross raised about 17 million dollars from the public, fed and sheltered hundreds of thousands of people, and supplied seed so that farmers could replant once the water had gone down. In many places, however, planting was so late that the 1927 harvest was poor, adding to hardship in the following year.

Racial injustice

The flood fell hardest on African Americans, many of whom worked as sharecroppers on Delta plantations. In Greenville, thousands of Black refugees were confined to the top of the levee in harsh conditions. Under the influence of local planter leaders, including William Alexander Percy, son of the former senator LeRoy Percy, they were prevented from leaving, partly because planters feared losing their labour force. National Guardsmen kept watch, and Black men were forced to work unloading supplies and repairing levees, often without pay.

Reports of abuse in the camps led Hoover to appoint a Colored Advisory Commission, chaired by Robert Russa Moton, head of the Tuskegee Institute. The commission documented many problems, though Hoover sought to limit public criticism. The experience pushed many Black families to leave the South, contributing to the Great Migration to northern cities such as Chicago and Detroit.

Consequences

The death toll was officially about 246, but historians think the true figure was higher, possibly 500 or more. Damage was estimated at several hundred million dollars at the time. The flood showed that the levees-only policy had failed.

In May 1928 Congress passed the Flood Control Act of 1928, which committed the federal government to flood control on the lower Mississippi. The Army Corps of Engineers adopted a new plan that combined stronger levees with spillways and floodways, including the Bonnet Carré Spillway above New Orleans, completed in 1931. The same system was tested again in later floods, including the Great Mississippi Flood of 1993.

Hoover’s prominence helped him win the 1928 presidential election, shortly before the onset of the Great Depression.

Key people

Herbert Hoover, the Secretary of Commerce, directed the relief effort and became known as a capable organiser, an image that helped carry him to the White House. Calvin Coolidge, the President, approved Hoover’s appointment but kept the federal government’s role limited and resisted calls for a special session of Congress.

LeRoy Percy, a former US senator and powerful Delta planter, and his son William Alexander Percy, who ran relief in Greenville, shaped the treatment of Black refugees there. Robert Russa Moton, president of the Tuskegee Institute, led the Colored Advisory Commission that investigated conditions in the camps.

By the numbers

Myths and facts

The flood inspired many blues songs, among them “When the Levee Breaks” by Kansas Joe McCoy and Memphis Minnie, recorded in 1929. Bessie Smith’s “Back-Water Blues”, recorded in February 1927, is often said to be about the Mississippi flood, but it was written before the great levee breaks and is usually linked to earlier flooding, probably on the Cumberland River around Nashville at the end of 1926.

The flood has continued to appear in literature and music. William Faulkner’s novella “Old Man”, published in 1939 as part of the book The Wild Palms, follows a convict on the flooded river in 1927, and Randy Newman’s 1974 song “Louisiana 1927” recalls the disaster for a later generation.

Timeline

• 1926, summer to December: Heavy rains swell rivers across the Mississippi basin.
• 1927, April: Levees begin to fail along the Mississippi and its tributaries.
• 1927, 21 April: The levee breaks at Mounds Landing near Greenville, Mississippi.
• 1927, 22 April: President Coolidge names Herbert Hoover to lead the relief effort.
• 1927, 29 April: Engineers dynamite the levee at Caernarvon below New Orleans.
• 1927, summer: Floodwaters slowly recede, though some areas stay flooded into August.
• 1928, 15 May: The Flood Control Act of 1928 becomes law.
• 1928, November: Herbert Hoover is elected President of the United States.

Why it matters

The Great Mississippi Flood of 1927 changed how the United States manages its largest river and established federal responsibility for flood control. It also laid bare racial injustice in the Jim Crow South and accelerated the movement of African Americans to the North.