Remembering the Great Flood of 1993: A Review of the Hydrometeorological Conditions


Fred H. Glass and James F. Sieveking, NOAA/NWS, St. Charles, MO


Charles E. Graves, Saint Louis University, Dept. of Earth & Atmospheric Sciences, St. Louis, MO


Chad M. Gravelle, NOAA/NWS OPG/University of Wisconsin/CIMSS, Kansas City, MO


Patrick S. Market and Patrick E. Guinan, University of Missouri, Dept. of Soil, Env. & Atmospheric Sciences, Columbia, MO

Scott Dummer, NOAA/NWS/MBRFC, Pleasant Hill, MO




Remembering the Great Flood of 1993: A Review of the Hydrometeorological Conditions


This presentation commemorates the 25th anniversary of the Great Flood of 1993, reviewing the hydrometeorological conditions associated with this prolonged catastrophic event.  This event which spanned the period from June-September 1993 was characterized by a seemingly endless series of intense rainfall-producing mesoscale convective systems, which individually resulted in life-threatening flash flooding and collectively resulted in historic river flooding within the Upper Mississippi and Missouri River Basins. Over twenty cases of 24 hour rainfall totals in excess of 6 inches were observed within the river basins with the most extreme MCSs. The Great Flood of 1993 produced 48 fatalities and remains the most costly non-tropical, inland flood event to affect the United States. Losses were initially estimated at $20 billion. The 2017 CPI-adjusted estimate of $36.3 billion represents nearly one-third of the total flooding loses for the period from 1980-2017. Some of the hydrometeorological aspects that will be reviewed include: above normal soil moisture and water storage conditions in the Upper Mississippi and Missouri River Basins resulting from a wet Fall 1992  and Winter 1992-93,  the frequency and geographical distribution of heavy rainfall, and the presence and persistence of anomalous large scale circulation patterns which favored a strong zonally oriented storm track, an atypically strong southerly low level jet responsible for moisture transport and lift, and a wavering quasi-stationary frontal boundary to focus repeated thunderstorm complexes and heavy rain episodes.