Flash Flooding and Debris Flows in California, January 14 to 17, 2023

Widespread heavy rain fell from late morning on January 14 through much of the afternoon. Rain accumulations of 1.25 inch to 2 inches were common across inland Orange County, resulting in widespread flooding reports. The following are reports of flooding from the Department of Highways.

Both lanes of the I-5 north offramp was 4th Ave was flooded in Santa Ana. Four vehicles were stuck in the flood waters.

Farther south, three vehicles were stuck in the flooded onramp to northbound I-5 at Crown Valley Pkwy in Laguna Niguel.

Heavy rain resulted in the flooding of Huffstatler Creek flowing over Huffstatler Road at 2nd St and 5th St; roads were closed due to flooding.

The Department of Highways reported a rockslide in the westbound lane of Highway 74 near Hot Springs Canyon Road. Over 1 inch of rain had fallen in the region.

Harmony Grove Rd flooded at Wilgren Drive near Elfin Forest with four feet of water flowing in both directions into Elfin Park. Rain of 1.25-1.50 inch was reported that afternoon.

Heavy rain of 0.50 to 1.00 inch was reported on the afternoon and evening of January 14. The right lane of southbound I-805 north of Clairemont Mesa Blvd was flooded, and at Murray Ridge Road was flooded. All lanes except the HOV were flooded and vehicles were unable to pass. 10 inches of water were reported in lanes 1 and 2.

Orange County Fire Authority reported a swiftwater rescue of a young adult clinging to a tree in a creek, with rapidly moving water below. The person was airlifted out with no injuries reported.

A series of storm systems in close succession brought very heavy snowfall to the San Bernardino County Mountains, with the first occurring along a cold front late on January 14 into the morning hours of January 15, with the second system close on its heels, producing additional snowfall late on January 15 to early on January 17. The first system produced light to locally moderate snowfall, with 4 inches of snow reported near Green Valley Lake, and up to 6 inches of snow near Big Bear with blowing snow also reported.

The second, colder, system produced very heavy snowfall, leading to impressive multi-day snow accumulations:|Broadcast media reported 20-28 inches of snow accumulation at 7,000-8,000 feet at Snow Valley.|Broadcast media reported 21 inches of snow accumulation at 7,100 feet at Bear Mountain Snow Summit.|The Department of Highways reported 16 inches of snow accumulation at 6,900 feet near Running Springs.|The Department of Highways reported 13 inches of snow accumulation at 6,900 feet at Barton Flats.|The Department of Highways reported 12 inches of snow accumulation at 6,800 feet at the Big Bear Yard.

A series of storm systems in close succession brought very heavy snowfall to the Riverside County Mountains, with the first occurring along a cold front late on January 14 into the morning hours of January 15, with the second system close on its heels, producing additional snowfall late on January 15 to early on January 17. The first system produced up to 11 inches of snow neat Mt San Jacinto at 8400 feet at the Long Valley Ranger Station at the top of the Palm Springs Tram. The second system had lower snow levels, with 4 to 6 inches reported as low as 5700 feet.

Moderate to heavy rain occurred across the San Diego County metro area from 5-7 pm, resulting in flooding of major freeways. Highway 94 at Euclid Ave was flooded in Lanes 3 and 4; I-5 at Mile of Cars north was flooded, with a large amount of water in all lanes making it difficult for vehicles to drive; I-805 Bonita Rd offramp was flooded.

Department of Highways reported two to three lanes of southbound I-5 bypass at Highway 56 was flooded. Vehicles were unable to drive in the slow lane.

Strong winds impacted the San Diego County Valleys the evening of January 14. The Department of Highways reported a downed tree, which took down cable wires and partially blocked vehicles on Eucalyptus Drive.

Trees were downed near Lake Elsinore, resulting in structure damage.

Heavy rain resulted in the closure of North Indian Canyon Road between Garnet Ave and Sunrise Pkwy due to flooding from the Whitewater River.

Very strong winds impacted the San Diego County Mountains from the morning on January 15 into early January 16. Two notable peaks in the winds occurred, with the first occurring near sunrise on January 15; the following are the peak gust reported from January 15:

Laguna Launch (SDHGPA) reported a peak wind gust of 75 mph.|Volcan Mountain reported a peak wind gust of 66 mph.

The second peak occurred before dawn on the 16th. The following are some of the top wind gust reports from the second surge event:

Palomar Mountain Lookout reported a peak wind gust of 74 mph.|Boucher Hill reported a peak wind gust of 62 mph.|Harrison Park reported a peak wind gust of 61 mph.

A series of Pacific storm systems produced widespread heavy rainfall across the San Diego metro area, producing rainfall totals of 3-5 inches near Fashion Valley from January 14-17, with the heaviest occurring the morning of January 15- the morning of January 16. The San Diego River reached 12.4-12.7 feet at Fashion Valley.

Every cross street in Mission Valley along the San Diego River was flooded, including toward the San Diego Trolley. Three vehicles were abandoned and under 2-3 feet of flowing water on Camino Del Este, Qualcomm Way and Fashion Valley Road. The San Diego River overflowed, with over 1 foot of standing water into the nearby parking structure.

Numerous swiftwater rescues were conducted, including one rescue of a woman whose car was completely submerged into the flood waters at Camino De La Reina and Avenida del No; a helicopter search for two victims was conducted near 4700 Pacific Highway, with five victims having been rescued from the water.

Hotel guests at the Riverleaf Inn were evacuated and vehicles were submerged in flowing water.

Heavy rain resulted in flooding at N Gene Autry Trail and at Vista Chino near the Whitewater Wash.

Four feet of flowing water was reported on Saturn Blvd from the Tijuana River. A stolen SUV was found in the water, though no one was seen near the vehicle; speculated that the vehicle had been stolen.

Strong winds impacted the San Diego County coastal areas through the early morning hours on January 16. Numerous trees were reported downed across the metro area:

A large pine tree fell on apartments on Marathon Drive in Mission Valley; some units were tagged as residents were unable to return.

A tree fell at 4059 Newton Ave. No injuries were reported, but residents were evacuated from the building.

A tree was downed into the roadway at Fortuna Ave and Ingraham St in Pacific Beach.

A large tree was downed at Archer and Cass St. Power outages of 2000 reported by SDG&E for Bonita and Pacific Beach.

A large tree landed on a vehicle at Playa Del Sur off of La Jolla Blvd.

A tree was reported down and blocking the road at 16292 Rambla De Las Flores.

Downed trees onto powerlines resulted in a road closure in Vista.

A retaining wall collapsed in Corona around 4:30 AM on January 16 resulting in twenty-four residents who had to evacuate their homes in nearby areas. One home was damaged immediately below the wall, and cracked the foundation above. Broadcast media reported that concrete blocks crashed down into adjacent properties, burying backyards and patios, and smashing through glass doors. Corona has received 1.5 to 3 inches of rain in the preceding 48 hours before the collapse.

San Diego County official reported flooding at on Pine Creek Crossing, resulting in the closure of the road.

Flooding was reported early in the morning on January 16 due to heavy rain, with the area having received 1.5 to 2 inches in the prior 12 hours, and 2.5 to 4 inches in the preceding 24 hours. Alpine Blvd was closed due to flooding, with flooding also reported south of Alpine due to the local creek.

Strong winds resulted in a downed tree in Valley Center, blocking all lanes of traffic at the intersection of Valley Center Road and Mac Tan Road.

Swift water rescue on Otay Lakes Road and milepost 8. Victim was rescued on top of the vehicle.

Heavy rain occurred across northern San Diego County on January 15-16, resulting in flooding near Rainbow. County officials announced the closure of Pala Mission Road near Highway 76, and Pala Temecula Road. Rainfall of 1 to 1.5 inch had been reported leading up to the flooding.

Harmony Grove Road closed due to flooding, with 1-2 feet of flowing water from the Escondido Creek. Rainfall of 2 to 3 inches had been reported in the prior 24 hours, with 4 to 5.5 inches in the 72 hours leading up to the flooding.

A woman was rescued by San Diego lifeguard after being stranded in her vehicle in four feet of water near the Tijuana River. 7 inches of rain had been reported at Otay Mountain in the preceding 3 days, with 4.2 inches of rain in Bonita.

Escondido Creek overflowed, and flooded fields and parking areas alongside the river and Rancho Santa Fe Road.

Flooding was reported at Honey Springs Road and Mother Grundy truck trail, with two feet of water over the road. Three inches of rainfall was reported in the 24 hours preceding the flooding.

The Department of Highways reported large boulders in the road on SR-78 and Wynola Road near Julian. That area had received 2 to 3 inches of rain in the preceeding 24 hours.

The Department of Highways reported water flowing across Cole Grade Road from the San Luis Rey River. Rainfall of 8 to 11 inches had been received in the 72 hours prior to the flood report.