Jul 21, 2018
A severe thunderstorm developed over the central Black Hills and tracked eastward through the Rapid City area before weakening over the plains. The storm initially contained large hail over the Black Hills, then also produced strong winds as it moved through the Rapid City area. Flash flooding also occurred in the Keystone and Rapid City areas due to two to three inches of rain.
Source: NOAA National Weather Service Storm Events Database (event 769596). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Pennington County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.