May 11, 2023
A prolonged rain event over several days led to flooding and flash flooding over the Cheyenne and White River basins. Three to five inches of rain fell, with some locations receiving nearly four inches of rain within six hours on the evening of May 11. As the water flowed into larger rivers, minor flooding was observed.
Source: NOAA National Weather Service Storm Events Database (event 1093363). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Oglala Lakota County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.