A powerful winter storm, fueled by an atmospheric river, brought very heavy rainfall and significant flash flooding to parts of Southwestern California. The heaviest rainfall occurred across the mountains of Santa Barbara, Ventura and Los Angeles counties with totals ranging from 5 to 14 inches while coastal and valley areas in these three counties reported 2 to 8 inches of rainfall. Across San Luis Obispo county, 2 to 5 inches of rainfall was reported. Numerous reports of flash flooding and mud and debris flows were reported across Santa Barbara, Ventura and Los Angeles counties.

Flash Flood in VENTURA, CALIFORNIA
From 21-DEC-23 02:01:00 to 21-DEC-23 06:00:00 (PST-8)
Location: WEST SATICOY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

California Highway Patrol reported flash flooding along Highway 126 around the Kimball Road on and off ramps.

Flash Flood in VENTURA, CALIFORNIA
From 21-DEC-23 02:40:00 to 21-DEC-23 06:30:00 (PST-8)
Location: OXNARD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flash flooding was reported around the intersection of Saviers Road and Elm Street in Port Hueneme.

Flash Flood in VENTURA, CALIFORNIA
From 21-DEC-23 02:51:00 to 21-DEC-23 06:30:00 (PST-8)
Location: (OXR)OXNARD ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flash flooding was reported near the intersection of F Street and 2nd Street. Over two feet of water flooded the area.

Debris Flow in VENTURA, CALIFORNIA
From 21-DEC-23 11:30:00 to 21-DEC-23 14:30:00 (PST-8)
Location: SANTA SUSANA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A rock slide was reported across the east-bound lanes near the intersection of Santa Susana Pass Road and Box Canyon Road.

Flash Flood in VENTURA, CALIFORNIA
From 21-DEC-23 12:20:00 to 21-DEC-23 15:30:00 (PST-8)
Location: LAGOL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

California Highway Patrol reported significant on Highway 118 at the intersection with Grimes Canyon Road. The flood waters eroded part of the road.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 09:04:00 to 21-DEC-23 12:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Significant flooding was reported on Highway 101 at the offramp for Mission Street. Over four feet of water flooded the offramp.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 09:37:00 to 21-DEC-23 12:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Significant flooding was reported along Highway 101 at the Castillo Street offramp. Vehicles were turning the wrong way to try to avoid the flooding. Eventually, both the onramp and offramp were closed.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 09:51:00 to 21-DEC-23 12:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Significant flooding was reported along Highway 101 at the Mission Street onramp and offramp. Hard closures were reported.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 10:01:00 to 21-DEC-23 12:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Significant flooding was reported along Highway 101 at the Garden Street onramp and offramp. Hard closures were reported.

Debris Flow in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 11:47:00 to 21-DEC-23 14:00:00 (PST-8)
Location: SUMMERLAND
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Significant mud and debris flows were reported along State Route 192 near the intersection of Cima Del Mundo Road.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 11:49:00 to 21-DEC-23 14:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Significant flooding was reported in the city of Santa Barbara. Several business, as well as the Superior Court House, reported significant flooding.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 11:50:00 to 21-DEC-23 14:00:00 (PST-8)
Location: SANTA BARBARA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Significant flooding was reported in the city of Santa Barbara. Numerous reports of vehicles stuck in flooded roadways, requiring rescues.

Flash Flood in SANTA BARBARA, CALIFORNIA
From 21-DEC-23 11:51:00 to 21-DEC-23 14:00:00 (PST-8)
Location: MONTECITO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Significant flooding resulted in the closures of Mountain Drive and Cold Springs Road.

Debris Flow in LOS ANGELES, CALIFORNIA
From 21-DEC-23 17:01:00 to 21-DEC-23 20:00:00 (PST-8)
Location: SUNSHINE HOMES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Mud and debris was reported across Vasquez Canyon Road, between Sierra Highway and Bouquet Canyon Road.

Debris Flow in LOS ANGELES, CALIFORNIA
From 21-DEC-23 12:55:00 to 21-DEC-23 15:00:00 (PST-8)
Location: PANORAMA CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Mud and debris flows resulted in the closure of Sheldon Street at the intersection of Interstate 5.

Debris Flow in LOS ANGELES, CALIFORNIA
From 21-DEC-23 13:06:00 to 21-DEC-23 16:00:00 (PST-8)
Location: WEST HOLLYWOOD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A significant mud and debris flow damaged a patio at a residence in Beverly Hills.