Weakening Hurricane Norbert helped draw significant moisture into southwest California on the 7th. Daytime heating utilized this moisture to set off scattered thunderstorms with heavy rain at times, mainly in Riverside and San Diego Counties. Local rainfall amounts of 1 to 2 inches fell over the city of Riverside, San Bernardino and Hemet, while the mountains in that county saw up to six tenths of an inch, near Sky Valley. Early morning thunderstorms on the 8th drenched parts of the the Coachella Valley which received one-third of an inch up to just over 3 inches near the lower foothill in Thousand Palms, and Bear Creek in La Quinta. Rainfall rates were up to 2 inches per hour at times, producing widespread flash flooding, most notably in the Coachella Valley on September 8th. Mud and water closed several roads and stranded countless vehicles in La Quinta, Palm Desert, and Thousand Palms. Homes in La Quinta were surrounded by water. The worse hit areas were Washington Street in La Quinta and Varner Road in Thousand Palms. Moving water was a deep as 3 feet on roads and 4 to 5 feet of standing water submerged vehicles and mud was several feet high on Varner Road. A complete storm survey was done in Riverside City and in the Coachella Valley.

Thunderstorm Wind in RIVERSIDE, CALIFORNIA
From 07-SEP-14 12:30:00 to 07-SEP-14 14:00:00 (PST-8)
Location: RIVERSIDE JCT
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

NWS survey found numerous trees downed by high winds from wet microburst. Most trees were snapped and a couple were uprooted. Trees blocked a couple roadways in residence just east of Chicago avenue. A couple trees were 2 to 3 feet in diameter. The same area had considerable flood damage to a sidewalk and concrete drainage ditch.

Flash Flood in RIVERSIDE, CALIFORNIA
From 07-SEP-14 11:30:00 to 07-SEP-14 13:00:00 (PST-8)
Location: VALLE VISTA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported road washing out at Cedar Avenue in Hemet, as well as flooding along Highway 74 at 1st Street across all lanes of 74. Also flooding was reported at Palm and 1st, with knee-deep water. The Hemet Valle Vista alert gage recorded 2.06 inches of rain over the past hour. A few miles east on Highway 74, an off-road vehicle was stuck in a flash flood, as well as another party of 2 were stuck in a house and couldn't cross the road due to water. County Roads closed Highway 74 1.5 miles from the ranger station at Doe Canyon Road.

Flash Flood in SAN DIEGO, CALIFORNIA
From 06-SEP-14 16:45:00 to 06-SEP-14 17:30:00 (PST-8)
Location: VALLEY CENTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

California Highway Patrol reported a river of flood waters washing across the road at the intersection of Highway 79 and Chihuahua Valley Road. They shut down the road at that spot.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 07-SEP-14 12:00:00 to 07-SEP-14 12:45:00 (PST-8)
Location: RUNNING SPGS
Flood cause: Heavy Rain
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported rocks 2 feet in diameter blocking lanes. CHP also reported a boulder hitting the windshield of a black Toyota Prius on Highway 330.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 07-SEP-14 12:30:00 to 07-SEP-14 13:30:00 (PST-8)
Location: NORTH LOMA LINDA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported water breaking through the right-side berm, flooding all southbound lanes of Interstate 215, blocking the 2nd Street exit.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 07-SEP-14 13:30:00 to 07-SEP-14 14:30:00 (PST-8)
Location: (VCV)GEORGE AFB VICT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported a power line down in the dirt and National Trails Highway starting to flood just south of Helendale at Bryman Road. Some vehicles are stopped and others moving slowly. Six vehicles are stuck due to the flood waters.

Flash Flood in RIVERSIDE, CALIFORNIA
From 07-SEP-14 12:30:00 to 07-SEP-14 13:00:00 (PST-8)
Location: HIGH GROVE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported the slow lane of Highway 60 at Main Street under at least 2 feet of water with several vehicles stuck in the water. CHP also reported one lane of the northbound University on-ramp to Interstate 215 is flooded. Also, all lanes of northbound Interstate 215 are flooded, except the HOV lane. Spotter 217 reported several locations flooded along Iowa Avenue in Riverside, near UC Riverside. Iowa Avenue at Center Street, Marlborough Street, and several other spots were under a foot or more of water, running up over the gutters and curbs. CHP also reported a woman stuck in her vehicle on the 14th Street on-ramp to eastbound SR 91. Several vehicles were also stuck in approximately 4 feet of water at the railroad crossing on 14th Street. CHP shut down both sides of the road there.

Flash Flood in RIVERSIDE, CALIFORNIA
From 07-SEP-14 14:30:00 to 07-SEP-14 15:00:00 (PST-8)
Location: (TRM)THERMAL ARPT
Flood cause: Dam / Levee Break
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

California Highway Patrol reported the canal at 66th Avenue and Harrison Street ruptured and completely flooded the intersection. The intersection was closed.

Flash Flood in RIVERSIDE, CALIFORNIA
From 08-SEP-14 03:30:00 to 08-SEP-14 04:30:00 (PST-8)
Location: NORTH PALM SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reports flooding and debris in all lanes on Dillon road and North Indian Canyon Drive. Starting at 0345 PST, the road started to flood with mud and water up to 4 inches deep.

Flash Flood in RIVERSIDE, CALIFORNIA
From 08-SEP-14 06:30:00 to 08-SEP-14 08:30:00 (PST-8)
Location: BERMUDA DUNES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported Country Club Drive at Starlight Lane flooded. Avenue 42 was also completely flooded between Adams and County Club drive and was closed at this location. CHP reported a vehicle flooded out and blocking the Washington Street on-ramp to westbound Interstate 10. CHP also reported flooding of the #1 and #2 lanes of Interstate 10 westbound at Washington and Monterrey streets. Flooding signs were placed at both locations. Water 3 to 4 feet deep submerged 4 to 5 vehicles at the intersection of Washington Street and Country Club Drive. Southbound Indian Canyon Road was also closed at I-10.

Flash Flood in RIVERSIDE, CALIFORNIA
From 08-SEP-14 05:00:00 to 08-SEP-14 06:30:00 (PST-8)
Location: THOUSAND PALMS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported 3 vehicles stuck in water, one of which has water up over the tires. Varner Road and Bob Hope Drive are closed. Two other vehicles stuck in water at Varner Road and Date Palm Drive. CHP reported heavy flooding in the center divide and #1 lane of Interstate 10 westbound. CHP reported 6 vehicles stuck in water on Ramon Road at Chimayo Road, with water covering the tires of at least one of the vehicles. CHP reported a stalled vehicle partially in the roadway and stuck in water on Ramon Road at Thousand Palms Canyon Road. As of 0830 PST, numerous vehicles were getting stuck and blocking Thousand Palms Canyon Road, so the wash was shut down at Frances, just east of Thousand Palms Canyon Road. The ALERT gage at Thousand Palms NE recorded 1.54 inches of rain between 0530-0630 PST.