By the time it reached Pacific Coast Highway late Thursday, the blaze had burned about 8,000 acres - or 12 1/2 square miles - and had forced the evacuation of a university and hundreds of homes, officials said.
The blaze was 10 percent contained, but the work of more than 900 firefighters and deputies was just beginning, Ventura County fire Capt. Bill Nash said.
"This fire is a long way from out," Nash said. "It is still growing."
Nash said gusts of nearly 30 mph were still being reported near the coast late Thursday, and the National Weather Service said strong Santa Ana winds and extreme fire danger would remain in the region through Friday.
Some 2,000 homes were threatened. Despite the fire's size and proximity to populated areas, no houses had been destroyed, though 15 were damaged and a cluster of RVs in a parking lot was destroyed by flames.
There were no reports of injuries.
After reaching the highway, the fire began burning along the seaside roadway south toward Malibu. Planes and helicopters dropped water and retardant until they were grounded by darkness. The day began with a staggering drop in humidity, a plunge from 80 percent to single digits in less than an hour caused by withering winds out of the northeast and temperatures in the 90s.
The fire erupted during morning rush hour along U.S. 101 in the Camarillo area about 50 miles northwest of Los Angeles, and winds pushed it down slopes toward subdivisions, soon forcing evacuations of residents in Camarillo and Thousand Oaks.
Marie Turner, 45, was among the displaced at an evacuation center in Thousand Oaks as flames skirted the home her family moved into from Texas less than a year ago. She said in a phone interview she had given little thought to wildfires and worried about an entirely different kind of California threat.
"I'd always heard about earthquakes, it was a big fear of mine before we moved here," said Turner.
She said she was frightened but didn't regret the move.
"I'm very positive about being here, and we're trying to make the most of it," said Turner.
The smoke-choked campus of California State University, Channel Islands was evacuated, and classes were canceled for Thursday and Friday. The school has about 5,000 students, though only a fraction live on campus.
About 100 miles to the east in Riverside County, two homes were destroyed, two more were damaged and 11 vehicles were destroyed in a 12-acre fire that fire officials suspect was started Thursday by a discarded cigarette.
Elsewhere in the county, a 4?-square-mile blaze that destroyed a home burned for a second day in mountains north of Banning. It was 55 percent contained.
Crews for a second day took on a 4?-square-mile fire burning in the foothills of the San Bernardino Mountains north of Banning, Riverside County fire spokeswoman Jody Hagemann said. The fire, which burned a home Wednesday, was 55 percent contained.
In Northern California, fire in Tehama County continued to grow, consuming 10,000 remote acres north of the town of Butte Meadows. No homes were threatened and it was 10 percent contained.