Wind gusts were forecast to top out at 70 miles per hour (115 km per hour) on Wednesday and remain strong through the week.
"We expect to be out here all week fighting and containing this fire", Los Angeles Mayor Eric Garcetti said.
Huge, fast-spreading wildfires in southern California have already destroyed at least 200 homes.
Los Angeles Fire Department crews are working both the Creek Fire, which Terrazas said may have burned 14,000 acres above Sylmar, and, on the other end of the city, the Skirball Fire, which erupted in Bel-Air before dawn Thursday.
More than 250,000 homes lost power, utilities said.
In San Bernardino County, two smaller fires sprang up.More news: Analysts are on the Bearish side about Callidus Software Inc
At least one home appeared to be in the path of the fire, aerial video showed. About 30 structures have been destroyed there.
California Gov. Jerry Brown declared an emergency for Ventura County, freeing state resources such as the National Guard to support response efforts.
One of the fires, the Creek fire, jumped from 4,000 acres to 11,000 acres in size over several hours Tuesday in Los Angeles.
Fires tore through neighborhoods, razing homes to the ground, reducing them to gray smoldering ashes.
"We also can look for hotspots, " Terrazas said.
The mandatory evacuations included a mobile home park in Lopez Canyon; Arroyo Street north of the Foothill (210) Freeway; a mobile home park on Maclay Street; and the Pacoima Wash west of Sayre Street.More news: Holowesko Partners LTD Continues to Hold Holding in American Express Co (AXP)
"Now, everything that I have, except for my lovely family, is gone", she said.
Meanwhile, the Rye Fire grew 2,000 acres overnight to 7,000 acres and spread from Santa Clarita, Los Angeles County, to the edge of Ventura County.
Hartwig, who was on site on Wednesday along with about 100 essential staff members, said he was still concerned that heavy winds might blow across the highway toward the Getty.
It is so bad that the National Weather Service - which normally uses yellow, orange and red to gauge how severe the wind will be on its graphs - created a whole new color, purple, to depict the extreme conditions expected Thursday.More news: Newmont Mining (NEM) Stock Rating Reaffirmed by Royal Bank Of Canada
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