Aug 3, 2017
The month began with a ridge of high pressure over the Great Basin and moderate easterly flow in the mid and upper levels. This allowed monsoon moisture to surge into the southern half of California August 1st-3rd. Severe storms occurred in the Inland Empire and San Diego County Valleys on the 1st. Storms focused more on the mountains and deserts on the 2nd and 3rd, with reduced intensity overall.
Source: NOAA National Weather Service Storm Events Database (event 719299). 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.