Sep 5, 2009
On September 5th, copious low-level moisture over the deserts combined with extensive daytime heating and an upper-level trough triggered a massive severe thunderstorm over the San Diego County deserts just south of Ocotillo Wells. Surface dew point temperatures in the area were as high as 75 degrees, with air temperatures reaching 105 degrees. According to radar data, storm tops were at least 60 kft. The storm, which was nearly stationary and lasted for over 90 minutes, produced flash flooding,
Source: NOAA National Weather Service Storm Events Database (event 196858). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in San Diego County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.