The fire came as the area was being hit by seasonal Santa Ana winds that forecasters said could develop into the worst windstorm in a decade.
Gusts of up to 100 miles (160 kilometers) an hour were expected in parts of Los Angeles and Ventura counties, the National Weather Service said.
Red flag warnings of critical fire danger — the highest level of alert — were expected to remain in place until Thursday evening.
“This looks pretty, pretty concerning,” said meteorologist Daniel Swain.
“It’s going to be, I think, a rough night. And what’s going on now is only just the beginning, because weather conditions are going to get a lot worse.”
Hollywood events including a red-carpet premiere of Jennifer Lopez’s new film “Unstoppable” were called off amid the blaze.
California Governor Gavin Newsom said Biden had instantly approved federal aid to tackle the fire.
“No politics, no hand wringing, no kissing the feet. The president of the United States said, ‘yes. What else do you need?'” he told reporters.
