The 1993 Upper Mississippi River Valley Flood
Normal Year Flood (1988):
Unprecedented 1993 Flood:
What happened: ?
In the summer of 1993, the Mississippi River basin in the midwestern United States experienced
anomalously high rainfall. Record flooding resulted from an abnormally persistent atmospheric
weather pattern consisting of a quasi-stationary jet stream positioned over the central part of the
nation; there, moist, unstable air flowing north from the Gulf of Mexico converged with unseasonably
cool, dry air moving south from Canada.
All time high discharge was seen:
a major flood of the entire Upper Mississippi River basin which
resulted in very wide spread agricultural and commercial damage.
On August 10, an enormous plume of turbid river water was detected extending eastward from the
Mississippi River delta region. River water discharged on the western side of the delta flowed eastward
around the south side of the delta, joining additional river water discharged from passes on the south
and east sides of the delta. The sediment plume covered 7000 km2, extending 270 km eastward onto
the Mississippi, Alabama, and Florida continental shelves to 87°30'W
This was a large scale catastrophe!