Sep 16, 2025
A nearly stationary thunderstorm developed and dissipated over southwestern Sioux Falls along a converging set of outflow boundaries from earlier thunderstorm activity. With less than 10 knots of deep-layer shear and an extensive warm-cloud depth, torrential rainfall occurred with 1 to 2 inches in less than an hour. Brief large hail also occurred at the onset of heavy rain.
Source: NOAA National Weather Service Storm Events Database (event 1292617). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Minnehaha County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.