Flash Flood — Riverside, California

2012-09-11 · near Mecca, Riverside, California

Event narrative

A stationary thunderstorm brought persistent heavy rain in Mecca between 0200 and 0800 PST, resulting in flash flooding of two mobile home parks. Approximately 15 to 20 mobile homes in the Duroville and Saint Anthony's mobile home parks were damaged. The American Red Cross set up an evacuation center at the Mecca Family and Farm Workers Services Facility for the approximately 1500 residents affected. A boil water message was issued for these locations as well. Saul Martinez Elementary School also reported water damage to 15 classrooms, the teachers' lounge and the administration building with 2 to 3 inches of water.

Wider weather episode

An upper-level low pressure area moving slowly northeast over the lower deserts, and an associated weak disturbance aloft triggered a slow moving thunderstorm in the lower Coachella Valley near the community of Mecca just after midnight PST. With abundant moisture extending from the surface to 400 mb, and precipitable water values between 1.8 and over 2.2 inches, this storm remained nearly stationary from approximately 0200 through 0800 PST and produced between 3 and 5.5 inches of rainfall near Mecca (approximately 30 miles southeast of Palm Springs, CA). In addition, radar estimates were between 5 and 8 inches. Most of the rain fell between 0200 and 0400 PST, which resulted in a rare and damaging flash flooding in this area. This was eventually found to be a 1000-year flood event.

View location on OpenStreetMap → (33.5683, -116.0814)

Source: NOAA Storm Events Database, event_id 415009. Narrative written by the NWS forecast office that issued the report.