Jul 8, 2015
A large thunderstorm complex developed within the warm sector of a low pressure system that tracked northeast across the St. Louis area. A deep southwesterly flow of tropical moisture provided fuel for the storms. Precipitable water values were approaching two inches. Isolated flash flooding occurred with the strongest and most persistent storms.
Source: NOAA National Weather Service Storm Events Database (event 587374). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Union County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.