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
Abstract:
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.