Scattered to numerous thunderstorms developed over portions of eastern Riverside County during the afternoon hours on September 8th and some of the stronger storms produced very heavy rainfall with peak rain rates in excess of 2 inches per hour as shown  by local radar. The intense rainfall led to episodes of flash flooding, especially along the Interstate 10 corridor from west of Desert Center westbound past Chiriaco Summit. The California Highway Patrol reported at least 2 locations where flooding was occurring across Interstate 10; fortunately no accidents were reported due to the very hazardous driving conditions. Flash Flood Warnings were issued at times during the afternoon due to the high risk of flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 08-SEP-17 13:45:00 to 08-SEP-17 17:00:00 (PST-8)
Location: DESERT CENTER
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Scattered to numerous thunderstorms developed across portions of eastern Riverside county, mainly east of Joshua Tree National Park, during the afternoon hours on September 8th. Some of the stronger storms produced very heavy rainfall with peak rain rates in excess of 2 inches per hour. The intense rains led to episodes of flash flooding that primarily affected the Interstate 10 corridor west of Desert Center and through Chiriaco Summit. At 1405PST the California Highway Patrol reported that Interstate 10 was flooded eastbound at Red Cloud. About forty five minutes later at 1450PST the California Highway Patrol reported that Interstate 10 was flooded at Chiriaco Summit. A Flash Flood Warning was then issued but was not in effect when these flooding reports occurred. Fortunately no accidents or injuries occurred as a result of the flash flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 08-SEP-17 14:00:00 to 08-SEP-17 17:00:00 (PST-8)
Location: EAGLE MTN
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Scattered to numerous thunderstorms developed across portions of eastern Riverside County during the afternoon hours on September 8th, and some of them produced very heavy rains with peak rain rates in excess of 2 inches per hour. The intense rains led to flash flooding in locations to the east of Joshua Tree National Park, along Highway 177 across the far north portion of the county and near the intersection of Highway 62. As of about 1600PST, multiple reports were received from the California Highway Patrol of debris and mud near the intersection of Highway 177 and Highway 62. The reports also indicated multiple cars and trucks stuck in a nearby wash. The intersection was closed as a result of the flooding. A Flash Flood Warning was not in effect at this time. Radar indicated that most of the significant, flash flood producing rains had occurred well to the south of this intersection, closer to Interstate 10 and communities such as Eagle Mountain. It is most likely that the heavy rain to the south of the flooded intersection flowed through various washes towards the north and in a roundabout fashion the floodwaters eventually reached the intersection of highways 177 and 62 and caused the flash flooding and debris over the roads.