Mississippi flood of 1973

1973 Mississippi River floods

Morgan City, Louisiana inundated during May 1973
Date	December 1972-June 1973
Location	Mississippi Valley, Mississippi River Delta
Deaths	33
Property damage	$252.7 million USD

The Mississippi flood of 1973 occurred between March and May 1973 on the lower Mississippi River. The flooding was the third most severe along the U.S.' Mississippi River during the 20th century.

A series of unusually cold winters in the river basin concluded in the winter of 1972-1973, when high precipitation saturated much of the watershed, especially in the Ohio Valley and lower Mississippi Valley. This was followed by more rain in early 1973, with river flow cresting on March 31 at Red River Landing, Louisiana, and a heavy snowmelt in the Rocky Mountains which caused western tributaries such as the Missouri and Arkansas to form a final catastrophic high in June. The flood resulted in the largest volume of water to flow down the Mississippi since the Great Mississippi Flood of 1927. Both the Bonnet Carre Spillway and the Morganza Spillway were employed. The Bonnet Carre was fully opened between April 7 and June 14 for a record 75 days. The 1973 flood was the first time the Morganza Spillway was opened: from April 19 through June 13.

At Memphis, Tennessee, the Mississippi was over flood stage for 63 days, more than that of the historic 1927 flood, and the river was above flood stage for an even longer 107 days at upstream Cairo, Illinois. Out of the seven largest floods on the Mississippi between 1927 and 1997, the 1973 event ranked third in both volume discharged and duration but only sixth in flood height. Over $250 million of damages were incurred mainly in the Mississippi Valley states of Missouri, Arkansas, Tennessee, Mississippi and Louisiana.