- Winds were blamed for pushing the giant Thomas fire from Ventura County into Santa Barbara County, leading to expanded evacuations Sunday.
- About 18,000 structures are under threat, including celebrity homes in seaside communities of Santa Barbara County.
- The menacing fire, now in its seventh day, has charred some 230,000 acres and destroyed 790 buildings, officials said.
- Late Sunday, containment dropped back to 10 percent from 15 percent previously, reflecting a huge jump in acreage burned in the past 14 hours.
Southern California's largest wildfire, a devastating blaze that has already destroyed hundreds of homes in Ventura County, continued to grow Sunday and was threatening seaside communities in Santa Barbara County and prompting new evacuation orders.
Officials say the largest, most destructive wildfire burning in Southern California is expected to grow as it enters its second week.
The Thomas Fire north of Los Angeles has burned more than 270 square miles, prompted tens of thousands of evacuations and destroyed nearly 800 structures.
The National Weather Service says gusts up to 40 mph are expected through Monday.
The 230,000-acre Thomas fire, now in its seventh day, is threatening an estimated 18,000 structures, according to Cal Fire.
"Over the last 12 to 14 hours, we've experienced some extreme fire behavior on the fire," Mark Brown, operations section chief of Cal Fire told reporters at a Sunday evening briefing.
He said the fast-moving blaze had moved some 7 miles to the west in a 12 to 14-hour period, burning about 56,000 acres in the process. As a result, officials revised containment downward, from 15 percent to only 10 percent.
Officials ordered mandatory evacuations for at least 1,000 residents in southern Santa Barbara County, including portions of Carpinteria. Also, evacuation warnings were issued for parts of Montecito and Summerland, two communities known for multimillion-dollar homes and celebrity estates.
Oprah Winfrey and actor Rob Lowe are among the famous with homes in the Montecito area. They both tweeted Sunday about the fire approaching the town and offering prayers.
Lowe tweeted Sunday morning that he was "packing to evacuate now."
Also, TMZ reported that Ellen DeGeneres' new home was under threat. She purchased a home in Carpinteria back in October.
As of Sunday, fire officials estimated the cost to date of fighting the Thomas fire at approximately $34 million.
California Gov. Jerry Brown visited fire areas Saturday and told reporters, "We're facing a new reality in the state where fires threaten people's lives, their property, their neighborhood, and of course billions and billions of dollars. So we have to have the resources to combat the fires."
Bone-dry Santa Ana winds were blamed for helping to spread the fire Saturday night, and weather forecasters said wind gusts were possible into Monday morning.
In Ventura County, the Thomas blaze continued to threaten portions of Fillmore and Ojai, as well as some unincorporated areas of the county.
Authorities lifted mandatory evacuation orders in the city of Ventura, where the fire destroyed entire neighborhoods. However, they cautioned that there remain hotspots in the city that could smolder for several days and flare up again.
There are nearly 6,000 firefighters battling the wildfire, including crews from Oregon, Colorado and other states. Also, at least four large firefighting aircraft are on the blaze, including 737 and DC-10 air tankers capable of dropping huge amounts of fire retardant.
"We have 29 helicopters assigned to this incident, and throughout the day they all flew the maximum amount of hours that they could fly," said Cal Fire's Brown. "Our air force on this fire is being used effectively."
The blaze has caused misery for people in the region since it's filled the air with smoke and ash. There also was at least one fire-related fatality on Wednesday, according to Ventura County officials.
As of Sunday, firefighters were battling five major wildfires in Southern California. Here's the latest on other wildfires in the region:
- The Creek fire in Los Angeles County stood at 95 percent containment Sunday evening after charring more than 15,600 acres and destroying 60 homes and damaging 80 structures.
- The Rye fire in Los Angeles County was 93 percent contained with just over 6,000 acres burned.
- The Skirball fire in Los Angeles County, which damaged or destroyed 18 structures, was at 85 percent containment after burning about 422 acres.
- The Lilac fire in San Diego, which scorched 4,100 acres and damaged or destroyed more than 200 structures, was 75 percent contained.
—The Associated Press contributed to this report.