"We're going to be at Mother Nature's mercy," Ventura County fire spokesman Tom Kruschke said.
The wind-whipped fire erupted Thursday in the Camarillo area, damaging 15 homes and a cluster of recreational vehicles in a parking lot. About 2,000 Ventura County homes remained threatened and evacuations remained in force although the fire line edged southwards toward Malibu. It was about 20 miles from the coastal enclave at daybreak.
The blaze was 10 percent contained but the work of more than 900 firefighters and deputies was just beginning, fire officials said.
The weather forecast called for parching single-digit humidity, highs in the 90s in some fire areas and morning winds of 20 to 30 mph with gusts to 45 mph — slightly down from a day earlier.
There's still a chance of "explosive fire spread" before winds begin tapering off in the afternoon and cooler weather begins to kick in, said Curt Kaplan, a National Weather Service meteorologist in Oxnard.
While winds calmed overnight, the fire that had burned about 12 1/2 square miles by Thursday night had increased to around 15 1/2 square miles by dawn.
"It has grown throughout the night," Kruschke said. "The fire has been coming down canyons all along Pacific Coast Highway and that's where we've been concentrating a lot of our effort."
Air tankers were expected to resume water and fire retardant drops after daybreak, which showed molten lines of flames along the oceanside ridges and a vast, black charred landscape behind. Few homes were in the immediate area.
Although the flames were generally heading seaward, the threat to homes behind its edge remained from hotspots and wind-driven embers, Kruschke said.
"The fire can jump up at any time and any place," he said. "There's that hot bed of coals out there covering thousands of acres."
The fire was driven by gusty Santa Ana winds that usually run from fall into March then are replaced by foggy mornings as an onshore flow of cool air comes in, Kaplan said.
"This is a very, very strange weather pattern for this time of year," he said. Instead of the onshore flow heading eastwards from the coast, cold storms in Colorado and further east have been pushing westward, and that air heats up and dries out as it roll downs through the California mountains, he said.
The pattern was expected to begin breaking up Friday afternoon, rapidly cooling over the weekend and there even could be a chance of rain in the fire area on Sunday, the meteorologist said.
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 through 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 Thursday that fire officials suspect was started by a discarded cigarette.
Elsewhere in the county, a 4 1/2-square-mile blaze that destroyed a home burned for a third day in mountains north of Banning. It was 65 percent contained.
In Northern California's Tehama County, a wildfire north of Butte Meadows grew overnight although an estimate of its size was revised down from more than 15 square miles to 10 square miles, state fire spokesman Daniel Berlant said.
The fire was 10 percent contained. It's burning in a remote area and is not posing an imminent threat to any structures.
Elsewhere in the region, crews expected to fully contain a 125-acre blaze in Sonoma County and a 200-acre fire in Glenn County on Friday.
Containment of a 55-acre fire in Butte County was expected this weekend.
Contributing to this report were Associated Press writers Raquel Maria Dillon in Banning, and Robert Jablon and Andrew Dalton in Los Angeles.
Copyright 2013 The Associated Press.