Jul 20, 2004
A thunderstorm developed in a near tropical atmosphere just east of Dubuque, Iowa along a weak boundary that stretched from Decorrah, to Dubuque, to near Sterling, Illinois. The very slow movement of the storm combined with high atmospheric moisture resulted in prolific rainfall rates. Due to the hilly terrain of the area, flash flooding quickly developed around 20 minutes after the downpour started. Rainfall with the storm varied with the co-op observer in town reporting 1.68 inches of rain
Source: NOAA National Weather Service Storm Events Database (event 5424378). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Jo Daviess County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.