Aug 22, 2025
Storms moved over portions of northeast South Dakota that had really no extra room for moisture from the preceding months of nearly constant rainfall. Thus, this moisture went straight into the Big Sioux and tributaries from the Watertown area down south to Castlewood. The COOP observer in Rauville would record 1.51 inches of rainfall pushing their monthly total up to 5.73 and a 3 month total of 23.32. The Watertown COOP would likewise come up with 1.86 inches, putting the monthly total at 5.85
Source: NOAA National Weather Service Storm Events Database (event 1291976). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Hamlin County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.