Flood and Hail in Wisconsin, May 14, 2001

Several clusters of severe thunderstorms moved southeast through parts of south-central and southeast Wisconsin during the late morning and early afternoon hours. They produced predominately damaging, large hail stones, ranging in diameter from 3/4 inch on up to an incredible 3.75 inches! Most reports indicated that hailstones were in the 1 to 2 inch diameter range, and at many locations the hailstones left the ground white. Isolated wind damage was noted in Columbia County where large trees and some power lines were toppled near Friesland.The city of Watertown, which straddles the Dodge and Jefferson County line, sustained the worst hail damage. Hail fell for about 10 to 15 minutes, with the largest stones of 2.50 to 3.75 inches falling for about 1 to 2 minutes. One person was injured when the large hail stones landed on their head. Roughly 7500 motor vehicles were damaged - namely broken windows and numerous dents in the sheet metal. It was noted that some of the hood dents looked as if a person had driven their fist into the sheet metal! Seven (7) greenhouses belonging to a city florist received serious glass damage, as well as plant damage. In addition, many skylight windows in residential homes and businesses were shattered. On the north side of Watertown, the large hail stripped bark off trees. Local residents mentioned that they had never seen anything like this hailstorm. The ground was white, and the hail didn't melt completely for several hours. Many motor vehicles in the Waterford area of western Racine County sustained hail damage. In the city of Brookfield, a moving car was struck by lightning. The driver was unhurt, but the vehicle's electrical system was fried, a rear window was shattered, the two rears tires were left in shreds, and holes 6 inches deep and 3 feet wide were blown in the pavement. Small stream and urban flooding was noted in the city of Kenosha. Pike Creek flowed over its banks in Washington Park. Rainfall totals of 1 to 2 inches in 1 hour were noted across parts of southeast Wisconsin as the storms rolled southeastward.Synoptically, low pressure moved southeast from the South Dakota-North Dakota border, with a warm front extending southeast through southern Wisconsin to northern Indiana. A strong low-level jet pumped warm, moist, unstable air directly into southern Wisconsin up over the warm front position. Upper level lapse rates became steep as colder air moved in from the northwest. No thunderstorm activity was noted west of a line from Portage (Columbia Co.) to Waterloo (Jefferson Co.) to Delevan (Walworth Co.).