Jul 22, 1997
A small cluster of thunderstorms developed in a very unstable airmass. Movement was very slow. In addition "training" occurred as the cells backdeveloped over the northern part of the county. The storms dumped 8 inches of rain on the town of Graettinger causing flash flooding. The flooding in the city was serious enough that the city sewage plant was inundated causing the sewage to spill into the river. Extensive flooding of homes in the area also occurred.
Source: NOAA National Weather Service Storm Events Database (event 5603028). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Palo Alto County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.