Sep 13, 2011
An upper level low pressure system spread considerable moisture into southeast California, and led the development of scattered thunderstorms over Riverside county on the 13th of September. The moisture content in the atmosphere was very high and the thunderstorms produced flash flooding during the morning hours. Some of the flooding occurred in Joshua Tree National Park, fortunately there were no injuries or fatalities caused by the flooding.
Source: NOAA National Weather Service Storm Events Database (event 335491). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Riverside County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.