The Mississippi River reaches its peak level in St. Louis during a record 77-day flood. During the extended flood, 33 people died and more than $1 billion in damages were incurred.
The roots of the 1973 flood go back to October 1972, when above-average rain began falling in the river basins that feed the Mississippi River. With more precipitation than normal coming down through the winter, the stage was set for flooding when hard rain came down in March. With most of the Midwest already saturated, the Mississippi began rising slowly to flood levels.
By the middle of March, flood waters began inundating some communities along the Mississippi. The worst of it came in early April when 6 million acres south of St. Louis, Missouri, were claimed by the river and many levees crumbled and failed.
As they moved downstream, the rising waters threatened the city of New Orleans. Officials decided to divert some of the water to Lake Ponchartrain and the Gulf of Mexico. This ended the threat to New Orleans, but came at the expense of hundreds of farms in the area. In some areas, the floods continued until June.
Floods of this type are not typically as deadly as flash floods because there is sufficient warning and time to evacuate flood regions. Those who died in this instance were largely residents who had resisted evacuation orders. Still, the flood devastated the economy of the region, as very few families had flood insurance and millions of acres of farm land were unusable for a full year following the flood.