What to Know
Widespread showers are expected Thursday as the storm makes its last push through Southern California.
Residents near burn scar areas in Ventura and Santa Barbara counties remain under mandatory evacuations.
The showers have been record-breaking as some areas faced up to five inches of rain.
The final surge from a three-day storm hammered a widespread part of Southern California Thursday with steady rain and triggered flood watches throughout the region.
Thursday marked the third consecutive day in a region that includes several wildfire burn zones, areas that are especially susceptible to flooding and dangerous mudflows. So far, there has been no repeat of the devastation triggered by a Jan. 9 downpour in Montecito below the Thomas fire burn zone.
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Santa Barbara County fire Capt. Dave Zaniboni said Thursday there have been no debris flows and no trouble with creeks or debris basins. The rain has been through cycles of intensifying and then backing off, but there have been no periods of intense rain in a short amount of time as happened in January.
Santa Barbara County authorities were also warning of fraudulent fliers posted in the area purporting to be from city. The fliers claimed the city would be "ground stability testing," but officials told residents there was no such thing and to call 911 if someone tries to enter residents' property on this claim.
In Los Angeles County, part of a hillside was washed away in an area of La Tuna Canyon that had been evacuated due to burn area slide concerns. The slide about one mile north of the 8300 block of La Tuna Canyon Road in the Sunland-Tujunga area blocked a drainage ditch. Water is collecting and causing the side of the road to crumble.
"Your neighborhood will get the rain today," said NBC4 forecaster Shanna Mendiola. "It is more widespread."
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Heavier doses of rain are expected into the afternoon.
A flash flood watch for urban areas in Los Angeles County went into effect late Wednesday and will remain through Thursday night, affecting Santa Monica and San Gabriel mountains. Santa Clarita is also under a flash flood watch, which is expected to remain through 5 a.m. Friday.
Rainfall rates of up to 0.66 inches per hour will be likely through Thursday evening.
The storm came ashore on the central coast and spread south into the Los Angeles region and north through San Francisco Bay, fed by a long plume of subtropical moisture called an atmospheric river. It also moved eastward, bringing the threat of flooding to the San Joaquin Valley and Sierra Nevada, where winter storm warnings for new snow were in effect on the second day of spring.
Record rainfall was recorded in five spots including Santa Barbara, Palmdale and Oxnard, where nearly 1.8 inches of rain had fallen by Wednesday evening. That's compared to the record of 1.3 inches set in 1937.
Nearly 5 inches of rain had fallen in northern San Luis Obispo County, while 2.7 inches fell in Santa Clarita, just north of Los Angeles and 2.6 inches was recorded at one spot in Santa Barbara County.
To the north, mud and rockslides closed several roads in the region, including Highway 1 at Ragged Point near Big Sur, not far from where the scenic coast route is still blocked by a massive landslide triggered by a storm last year.
Evacuations Still in Effect for Some Areas
With the storm expected to last through Thursday, there was concern about the combination of rainfall rates and the long duration, said Suzanne Grimmesey, a spokeswoman for Santa Barbara County. Santa Barbara County ordered evacuation of areas along its south coast near areas burned by several wildfires dating back to 2016.
"We actually do feel good about the evacuation order," Grimmesey said. "Law enforcement was out in the extreme risk areas of Montecito yesterday knocking on doors. For those that were home, we had a very good cooperation rate with people leaving."
Many residents in Santa Barbara and Ventura counties have faced repeated evacuations or advisories since December, when a wind-driven fire grew into the largest in recorded state history and destroyed more than 1,000 buildings.
In Los Angeles County, authorities canceled some planned mandatory evacuations because of a projected decrease in rainfall but kept others in place because of debris flows in one canyon area stripped bare by wildfire.
Details on evacuation sites and shelters can be found here.