SANTA BARBARA, California (CNN) -- A wildfire that has engulfed dozens of homes and displaced thousands of people kept roaring in Southern California late Friday, scorching about 8,600 acres, fire officials said.
"We have a lot of resources on the line -- our folks are working their hearts out," Joe Waterman of the California Department of Forestry and Fire Protection told reporters.
An estimated 30,500 residents of Santa Barbara County have been ordered to evacuate because of the blaze, which has damaged or destroyed at least 80 homes, emergency officials said.
More than 12,200 homes or businesses are in the mandatory evacuation area.
Santa Barbara County Fire Chief Tom Franklin said the fire has displayed a "roller coaster effect" because of the changing weather patterns.
"It starts off, looks kind of calm, thinking we're getting the upper hand, turns out we're not," Franklin said. "As unpredictable as the weather can be, that's about as unpredictable as the fire is going to be."
The fire has engulfed mansions in the coastal community's foothills after starting Tuesday in the Cathedral Peak area.
It was about 10 percent contained by Friday morning, fire officials said. Nearly 2,500 people are working on battling the blaze.
The massive blaze was only about 10 percent contained by Friday evening, officials said. Fire officials hoped winds would die down late Friday and cooling temperatures would help them fight the blaze.
But that's the same thing that was expected Thursday night, when the direction of the winds unexpectedly flipped, blowing the fire back toward the sprawling mansions and other homes that dot the hills of the coastal community.
The winds that began blowing around sundown Thursday topped 50 mph.
Santa Barbara City Fire Chief Andrew DiMizio praised firefighters, who battled a fire front nearly five miles long on Thursday.
"They were dealt with a deck a cards that was pretty haphazard," DiMizio said.
The cause of the fire is unknown, and authorities are asking anyone with information on its origin to call a tip line.
The blaze comes about six months after the Tea Fire destroyed about 200 homes in the Santa Barbara area.