Jul 29, 2025
Thunderstorms erupted within a very moist and unstable environment across central South Dakota during the afternoon of July 29 in response to an approaching upper level short-wave from Colorado. These thunderstorms quickly grew upscale into a line, producing 55 to 75 mph wind gusts across southeast South Dakota and extreme northeast Nebraska, resulting in isolated tree damage. In addition, prolonged heavy rain resulted in some localized flash flooding across northwest Iowa.
Source: NOAA National Weather Service Storm Events Database (event 1288623). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Sioux County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.