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James Quigg
Janet waits for her bus under the cover of a new umbrella at a bus stop in Adelanto, Calif., as rain began to fall on Wednesday, March 21, 2018. (James Quigg/The Daily Press via AP)

LOS ANGELES — A powerful storm spread more rain across California on Thursday, flooding streets and threatening to unleash mud and debris flows into communities near areas burned bare by wildfires.

The National Weather Service said there were numerous reports of street flooding in the Central Valley cities of Fresno and Clovis.

A flood warning was issued for areas east and south of Sacramento as rain caused the lower San Joaquin River system to rise along the western flank of the Sierra Nevada.

In the south, the weather service warned of potential flash floods as radar showed heavy rain falling near recent burn areas in coastal Santa Barbara and Ventura counties, where thousands of residents were ordered to evacuate two days earlier.

Authorities kept a close watch on Santa Barbara County, hoping there would not be a repeat of the massive January debris flows from a burn area that ravaged the community of Montecito and killed 21 people.

The storm came ashore earlier in the week 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 or a "Pineapple Express" because of its origins near Hawaii.

It also moved east into the central California interior and Sierra Nevada, where winter storm warnings for heavy snow were in effect and many routes required motorists to put chains on their vehicles.

Numerous areas reported daily rainfall records.

Road crews were kept busy clearing mud and rocks from roads, while traffic accidents soared on slick streets.

Carolyn Potter, 59, evacuated from her home in Casitas Springs in Ventura County on Wednesday — the fourth time since September — and planned to sleep in her car in a grocery store parking lot to avoid hotel costs and the bustle of an evacuation shelter.

Meanwhile her husband Alan was staying home, just like he had the other three times Potter has evacuated because of fires or storms since September.

"I feel better not being under the cliff in my sleep," Potter said. "If he feels OK that's his problem. If something happens maybe I'll zip on down and dig him out."

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.

With the grim Montecito experience in recent memory, Santa Barbara County ordered evacuation of areas along its south coast near areas burned by several wildfires dating back to 2016.

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"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.