Tens of thousands have fled their homes as a brush fire in the Pacific Palisades has burned nearly 20,000 acres as of Thursday. Fire crews are actively working to contain the flames and stop any forward progress.

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.

Multiple wildfires are currently raging through Los Angeles County, forcing evacuations and destroying neighborhoods. A long dry summer created ample fuel that has combined with a lack of rainfall over the winter to extend fire season conditions.

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

Already known for having some of the worst air quality in the U.S., people in Southern California are now also at risk of inhaling smoke.