Tens of thousands of people have fled their homes as a brush fire in the Pacific Palisades has grown to nearly 20,000 acres on Thursday.

Forecasters are warning of a “life-threatening and destructive” windstorm expected to last several days and affect a massive swath of Southern California beginning early Tuesday. The offshore winds will be dry,

High pressure is building from the north and that will help to tighten the pressure gradient over southern California, producing more gusty winds.

Winds have begun shifting to the east, which drove the Eaton fire toward Arcadia and Monrovia early Wednesday morning. Smoke will more likely begin to blow into the eastern San Gabriel Valley, not as much to the south of the fire, Lyou explained. “Arcadia, Duarte and Azusa may see elevated levels (of bad air) from that fire,” he said.

The smoke was expected to most heavily affect northwest coastal LA County, and in areas nearest the Palisades, Eaton and Hurst wildfires.