Flash Flooding and Flooding in Wisconsin, July 20 to 21, 1999

A series of thunderstorms feeding off of a humid tropical-like airmass repeatedly trained across portions of southcentral and southeast Wisconsin during the late evening of the 20th into the early morning hours of the 21st. The net result was widespread flash flooding. There were numerous reports of shoulder washouts of roads and basement flooding. There were also many reports of stalled vehicles due to high water levels on many roads. One rainfall observer located 6 miles northeast of Beaver Dam in Dodge county reported 5.0 inches of rain between 2030CST and 2350CST on the 20th, with a total amount of 6.08 inches through 0620CST on the 21st.Northern Dodge County was hit by 2 separate flash flood rounds. Numerous roads had standing water 3 to 5 feet deep and some country roads experienced shoulder washouts. A stretch of railroad tracks were washed out in Iron Ridge. Elsewhere, rainfall rates of 1 to 1.5 inches an hour were reported in Washington county, and at West Bend 4.10 inches was measured from 2300CST on the 20th to 0700CST on the 21st.Similar rainfall rates were reported in Milwaukee county resulting in the Root River in the southern part of the county rising out of its banks. The Menomonee river in the Wauwatosa area (Milwaukee Co.) crested at 13.03 feet at 0145CST on the 21st, or 2.03 feet above flood stage. In the city of Milwaukee, a TV station reported 2.66 inches of rain between 2300CST on the 20th to 0100CST on the 21st. Law enforcement officials reported 1 to 2 feet of water on many roads, including the Interstate Highways, in and around the city of Milwaukee. In neighboring Waukesha County, 3 to 4 feet of standing water was reported on Interstate 94 near Pewaukee! Homes in Poynette and Pardeeville in Columbia county had homes with flooded basements, and 1 to 2 feet of standing water was reported on low spots of Highway 12 and other area roads near Lake Delton in Sauk County. Rainfall totals of 2 to 3 inches were noted around Lake Delton. Elsewhere, the Rock River at Waupan in Dodge County peaked 14 inches above its flood stage later on during the afternoon hours of the 21st.