Flash Flood and Hail in Michigan, September 6, 1999

A slow moving cold front drifted into southeast Michigan during the late afternoon and early evening hours, igniting thunderstorms as it went. Only one storm became severe, dumping quarter-sized hail in Shelby Township, just north of Utica. The storms were slow moving, and so produced locally heavy rain. A spotter in Shelby Township measured 3.41 inches of rain as the storms passed. Flash flooding closed a new section of state highway 59 (M-59), near Mound Road just west of Utica. The flooding occurred in the recessed freeway, due to a combination of runoff from the heavy rain, and the failure of a pumping system designed to keep the highway dry. A lightning strike may have contributed to the failure of the pumping system. Several vehicles had to be abandoned in the rising water, and the freeway was closed for several hours to clean up the water and mud left behind. In addition, minor flooding occurred at an apartment complex in Utica.The heaviest rain in all of southeast Michigan fell in Washtenaw County, between Saline and Manchester, where around 4 inches of rain occurred. However, no flooding problems occurred in this rural area. At Detroit Metropolitan Airport, 76 flights were delayed due to the thunderstorms. Part of a terminal at the airport suffered water damage, as a roofing project was in progress when the storms hit.