THE GREAT USA FLOOD OF 1993

Lee W. Larson

Office of Hydrology

NOAA, National Weather Service

Silver Spring, Maryland, USA 20910

From May through September of 1993, major and/or record flooding occurred in the Mississippi river basin across the states of North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Iowa, Missouri, Wisconsin, and Illinois. Fifty flood deaths occurred, and damages approached 15,000 million U.S. dollars. Hundreds of levees failed along the Mississippi and Missouri rivers. The magnitude and severity of this flood event was simply overwhelming, and it ranks as one of the greatest natural disasters ever to hit the United States of America. Approximately 600 river points where flood observations and N.W.S. forecasts are made in the Midwestern United States were above specified flood stage at the same time. Nearly 150 major rivers and tributaries were affected. It was certainly the largest and most significant flood event ever to occur in the United States. Tens of thousands of people were evacuated, some never to return to their homes. At least 10,000 homes were totally destroyed, hundreds of towns were impacted with at least 75 towns totally and completely under flood waters. At least 15 million acres of farmland were inundated, some of which may not be useable for years to come. Transportation was severely impacted. Barge traffic on the Missouri and Mississippi Rivers was stopped for nearly 2 months. Bridges were out or not accessible on the Mississippi River from Davenport, Iowa, downstream to St. Louis, Missouri. On the Missouri River, bridges were out from Kansas City downstream to St. Charles, Missouri. Interstate highways 35, 70, and 29 were closed. Ten commercial airports were flooded. All railroad traffic in the Midwest was halted. Numerous sewage treatment and water treatment plants were impacted. In this paper a brief description of the precipitation and flood characteristics is given along with suggested research topics.