A high impact mini atmospheric river impacted Southern California January 14th and 15th which brought heavy rain and snow to the region. Seal Beach reported 2 inches of rain in 2 hours, which caused extensive flash flooding. Water was up to doorways outside of homes, and the Pacific Coast Highway was closed for over a day in Huntington Beach due to flooding. Rainfall rates remained below flash flood thresholds at the Holy and Cranston burn scars during this mini-AR event. Dense fog was reported in the Cajon Pass on the morning of January 16th, which resulted in a 19-car pileup and 35 patients with minor to moderate injuries.
A larger atmospheric river moved into Southern California on January 17th, bringing heavy rain and snow to the region. Extensive flash flooding occurred due to the heavy rain. Swift water rescues occurred on the Santa Ana River in Riverside due to flooding. Rainfall rates exceeded flash flooding thresholds for the Holy fire burn scar on the 17th.
Overall, 6 to 12 inches of rain fell in the Santa Ana and San Bernardino County Mountains between January 14-17. Snowfall amounts in the mountains ranged from 4 to 12 inches above 6500 ft. Major surf and coastal flooding occurred during this event as well, which resulted in extensive damage of the Ocean Beach Pier in San Diego County.

Flash Flood in RIVERSIDE, CALIFORNIA
From 16-JAN-19 13:00:00 to 16-JAN-19 15:00:00 (PST-8)
Location: EL CERRITO
Flood cause: Heavy Rain / Burn Area
Property damage: 20.00K
Crop damage: 10.00K
Reported by: Fire Department/Rescue

Flash flooding from heavy rainfall over Holy fire scar in Trilogy parkway and Glen Eden with water going around homes.

Heavy Rain in ORANGE, CALIFORNIA
From 15-JAN-19 20:00:00 to 15-JAN-19 21:00:00 (PST-8)
Location: HUNTINGTON BEACH
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Huntington Beach received 1.25 inches of rainfall in one hour between 2000 and 2100 PST on January 15th. Local officials closed the Pacific Coast Highway (route 1) at approximately 9pm January 15th and kept it closed through the afternoon hours of January 16th.

Heavy Rain in ORANGE, CALIFORNIA
From 15-JAN-19 20:00:00 to 15-JAN-19 22:00:00 (PST-8)
Location: FOUNTAIN VLY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Fountain Valley received 2 inches of rain in 2 hours between 2000 and 2200 PST on January 15th. An industrial roof collapsed due to water build up at approximately 2200 PST on Mt. Hermann Street.

Dense Fog in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 16-JAN-19 09:30:00 to 16-JAN-19 13:30:00 (PST-8)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Local media reported a 19 car pileup on southbound I-15 in the Cajon Pass due to dense fog in the morning hours of January 16th. 35 patients were treated  for minor to moderate injuries.

High Wind in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 17-JAN-19 17:50:00 to 17-JAN-19 18:50:00 (PST-8)
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Burns Canyon Mesonet reported a peak wind gust of 65 knots between 1750 and 1850 PST on January 17th.

High Wind in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 17-JAN-19 18:00:00 to 17-JAN-19 19:00:00 (PST-8)
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Harrison Park mesonet station reported a peak wind gust of 55 knots between 1800 and 1900 PST on January 17th.

High Wind in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 17-JAN-19 17:30:00 to 17-JAN-19 18:30:00 (PST-8)
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Snow Peak mesonet reported a peak wind gust of 54 knots between 1730 and 1830 PST on January 17th.

Flash Flood in RIVERSIDE, CALIFORNIA
From 16-JAN-19 11:00:00 to 16-JAN-19 14:00:00 (PST-8)
Location: GLEN AVON
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 1.00K
Reported by: Department of Highways

Highway 60 had lane closures due to heavy rain bands of 0.50 to 0.75 per hour. Multiple swift water rescues on the Santa Ana River including helicopter extractions along Fleetwood and Via Ricardo.

Flash Flood in ORANGE, CALIFORNIA
From 15-JAN-19 20:00:00 to 15-JAN-19 22:00:00 (PST-8)
Location: SEAL BEACH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Heavy rainfall began 7 pm on January 15th and inundated downtown Seal Beach. The heavy rain also affected parts of Huntington Beach and Fountain Valley. The flooding in Seal Beach old town affected homes with water entering garages and first levels. The Pacific Coast Highway was closed through the 16th due to the flooding and standing water. Radar estimated 2 inches of rain in about 2 hours with totals over 3 inches across northwest Orange County.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 17-JAN-19 10:30:00 to 17-JAN-19 13:30:00 (PST-8)
Location: RUNNING SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported a mud/rock slide on Highway 18 at Live Oak Drive due to heavy rain.

Flash Flood in RIVERSIDE, CALIFORNIA
From 17-JAN-19 09:30:00 to 17-JAN-19 13:30:00 (PST-8)
Location: ARCILLA
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported Temescal Canyon Road at I-15 south closed due to flooding.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 17-JAN-19 13:00:00 to 17-JAN-19 16:00:00 (PST-8)
Location: CEDAR PINES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported 2 ft of water along Hwy 138 north of Cedarpines Park. A car stalled in the water, and 2 people had to be rescued.

Flash Flood in SAN DIEGO, CALIFORNIA
From 17-JAN-19 12:00:00 to 17-JAN-19 15:00:00 (PST-8)
Location: PALA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported highway 76 at Adams Drive flooded due to heavy rain.