Jul 24, 2025
A cluster of thunderstorms erupted within a very moist and unstable airmass ahead of a slow moving frontal boundary during the evening of July 23. These thunderstorms bisected the city of Sioux Falls from southwest to northeast with neighborhoods southeast of I-229 reporting 2 to 5 inches of rain in a matter of 1-2 hours. This resulted in significant flash flooding across impacted portions of the city. Later in the evening, a large mesoscale convective system across Nebraska moved north and east
Source: NOAA National Weather Service Storm Events Database (event 1287280). 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.