Widespread totals of 3 to 6 inches and localized higher amounts have been recorded in coastal mountain ranges, with 3 to 4 inches in many larger urban areas in the past few days, as a sprawling area of low pressure stalled nearby and then slowly drifted toward the coast. It remains off the shore of Southern California, ready to deliver more downpours before exiting Friday night.
“Heavy rain redeveloping offshore will move into the coast through this morning,” the National Weather Service wrote in a forecast discussion Thursday for the Central and Southern California coast and adjacent mountains. “Flash flooding (is) likely as up to 1 inch per hour rainfall rates move over the same areas hit with 2 to 6 inches of rain last night.”
Many of the areas that were flooded Wednesday night are under a Level 3 of 4 risk for excessive rainfall through Thursday.
A flood advisory covered the area from just west of Santa Barbara southeast to Malibu until 1 p.m. local time Thursday, where 1.5 to 4 inches of rain had fallen, with 1 to 4 inches more possible.
In Oxnard, the Fire Department said “many of the streets and intersections are heavily impacted by flooding,” in a post on X early in the day. “Please stay off the city streets for the next several hours until the water recedes.”
The Weather Service also received reports of flooding in Ventura and Port Hueneme, where evacuations were ordered.
Multiple stretches of Highway 101 in Santa Barbara County were flooded, and a portion of Highway 1 was closed in San Luis Obispo County. Boulders were reported on the road near Chatsworth in Ventura County and near Goleta in Santa Barbara County.
Early Thursday, as the lumbering storm system meandered offshore, slow-moving bands of torrential rainfall focused from around Santa Barbara to Oxnard and inland to the Topatopa Mountains. Significant rain also was falling around Los Angeles.
The Santa Barbara area has received about 2 to 3 inches of rain. Totals of 2 to 3 inches also were reported southward along the coast through Ventura and Oxnard. Areas including Malibu, Long Beach and much of the western Los Angeles metro also received at least 1 to 2 inches of rain.
In some places, rain was intense, falling at rates of 1 to 2 inches or higher per hour. A weather station in Oxnard recorded 3.1 inches in one hour Wednesday night, a rate the Weather Service called “extreme.” The average rainfall there for the month of December is just above 2 inches.
Amid the barrage of flooding rain, several tornado warnings were issued near Oxnard on Wednesday night. On Tuesday, the same storm system produced an EF1 tornado near Oroville, Calif., about 60 miles north of Sacramento.
A sampling of 72-hour rain totals in California as of Thursday morning include:
- 4.92 inches in Big Sur
- 4.60 inches in Oxnard
- 3.85 inches in Ventura
- 3.84 inches in Santa Barbara
- 3.72 inches in Redding
- 3.54 inches in San Luis Obispo
- 3.27 inches in Thousand Oaks
- 3.01 inches in San Francisco
- 2.96 inches in Bel Air
Even higher totals have come in from the coastal ranges:
- 8.86 inches at Old Man Mountain northeast of Santa Barbara
- 8.62 inches at Three Peaks south of Monterey
- 7.88 inches at KTYD Radio Towers on outskirts of Santa Barbara
- 7.03 inches in Los Alamos northeast of Lompoc
- 6.60 inches at Girard Ridge near Shasta
- 6.31 inches in the Santa Cruz Mountains south of San Francisco
Significant snowfall totals of about 10 to 24 inches have largely been confined to the higher elevations of the Sierra Nevada. Mammoth Mountain at 8,000 feet elevation has reported 9 inches over the past three days with snow continuing.
Storms continued to pummel the region west and northwest of Los Angeles Thursday morning as the threat of flooding remained, especially from Oxnard inland to Santa Clara.
The heaviest rain was forecast to shift northward during the day Thursday into San Luis Obispo, Monterey, Kings, San Benito and southwest Fresno counties. While bursts of heavy rain are possible, the rain Thursday into Friday is not expected to be quite as heavy as earlier in the storm.
“Rainfall rates for the most part will be around .3 to .6 inches per hour but there is a possibility for double those rates under heavier cloud bursts. 1 to 3 inches of additional rain is likely today but there could be more,” the National Weather Service in Los Angeles said.
Waves of showers and thunderstorms were expected to continue Thursday night into Friday morning along the coast from San Diego to Santa Barbara County, including Los Angeles, Ventura and Orange counties, and inland through western Riverside, far southwestern San Bernardino, southern and western Kern, and southern San Luis Obispo counties.
Showers and storms should then linger Friday afternoon into the evening from around Los Angles toward points east, including San Diego, Imperial and Riverside counties, as well as portions of San Bernardino County, with the precipitation finally moving away to the east late Friday night.
A drier stretch follows for at least a few days before rain reenters the forecast later next week.