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.

Resulting in:

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!