Fire Department spokesman Margaret Stewart says the fire was reported at 4:52 a.m. and is burning uphill, driven by the landscape rather than winds.
The Los Angeles Police Department ordered mandatory evacuations and the California Department of Transportation closed Intereste 405 between Highway 101 and Interstate 10.
The Bel-Air fire ravaged Bel-Air and Brentwood over two days, destroying more than 500 homes - including those of some celebrities. The evacuation order was later expanded, covering a large area bounded by Mulholland Drive to the north, Sunset Boulevard to the south, the 405 to the west and Roscomare Road on the east.
The strong, desiccating Santa Ana winds have created ideal conditions for wildfires, by compressing hot air in the L.A. basin, and prompting the spread of embers well ahead of any fires that crop up.
The fire had burned 7,000 acres and was 5% contained Wednesday morning, Medina said.
"This has only just begun", he said Tuesday. Firefighting crews were setting up on the southbound side of the 405 to prevent the fire from jumping the freeway, and northbound vehicles were being turned back. People who live in Mandeville and Sullivan canyons should be prepared to leave their homes, authorities said. Helicopters on sight. Evacuation centers set up at rec centers. The video shows the surrounding hillsides engulfed by a raging wildfire. The Pomona Fairplex and the Antelope Valley Fairgrounds in Lancaster also opened stables for evacuated animals. The Los Angeles County Sheriff's station in Santa Clarita reported its 911 emergency phone system had failed due to a power outage. Los Angeles Mission College's Main Campus at 13356 Eldridge Ave. and the East Campus at 12890 Harding St., both in Sylmar, were closed for the day, but there was no immediate word if classes would resume today.