A strong upper level low pressure system moved into far southeast California during the early morning hours on October 13th and triggered the development of widespread showers and thunderstorms. Many of the stronger thunderstorms produced intense and very heavy rain that led to episodes of flash flooding across portions of eastern Riverside County.  Park and Forest Service personnel reported many paved roads in Joshua Tree National Park flooded and washed out starting shortly after midnight. Flash flooding was also observed just north of the Salton Sea, with roadway flooding near the Salton Sea State Recreation Area. In addition, local law enforcement reported flash flooding near Interstate 10 at about 0230 PST, about 10 miles east of Desert Center. Multiple Flash Flood Warnings were issued for the area during the early morning hours. Fortunately, no accidents or injuries were reported due to flash flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 12-OCT-18 23:30:00 to 13-OCT-18 03:45:00 (PST-8)
Location: FERRUM
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A vigorous upper level low pressure system moved into eastern Riverside County shortly after midnight and triggered the development of numerous showers with embedded thunderstorms. Some of the stronger storms generated very heavy rain, with peak rain rates in excess of 2 inches per hour. The intense rain led to flash flooding just north of the Salton Sea and near the Salton Sea State Recreation Area. According to local law enforcement, at 0005PST flash flooding was observed at State Route 111 and Bay Drive. No accidents were reported due to the flash flooding. A Flash Flood Warning was in effect at the time of the flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 12-OCT-18 23:30:00 to 13-OCT-18 03:45:00 (PST-8)
Location: CHIRIACO SUMMIT
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

A strong upper level low pressure system moved east and into Joshua Tree National Park around Midnight on October 12 and triggered the development of widespread showers along with embedded thunderstorms. Some of the stronger storms generated intense rain with peak rain rates over 2 inches per hour. The heavy rain led to episodes of flash flooding across Joshua Tree National Park during the very early morning hours on October 13. According to the Park and Forest Service, at 0030PST flash flooding caused most of the paved roads, including Pinto Basin Road and Highway 62 near the town of Joshua Tree, to become closed. Pretty much all of the dirt roads around Joshua Tree National Park were also closed. Flash Flood Warnings were issued for the park due to the heavy rain and flooding. Fortunately there were no reports of accidents or injuries in the park due to the flash flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 13-OCT-18 02:00:00 to 13-OCT-18 04:45:00 (PST-8)
Location: DESERT CENTER ARPT
Flood cause: Heavy Rain
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A strong upper level low pressure system moved east and across eastern Riverside County during the early morning hours on October 7th. The low triggered the development of numerous showers and embedded thunderstorms, and some of the stronger storms generated intense rain with peak rain rates in excess of 2 inches per hour. The heavy rain led to episodes of flash flooding, including one along Interstate 10. According to local law enforcement, at 0233PST flash flooding occurred on East Corn Springs  Road near Interstate 10. Fortunately there were no accidents or injuries due to the flooded road. A Flash Flood Warning was in effect at the time of the flooding.