Tens of thousands of people were forced to flee their homes as a brush fire in the Pacific Palisades grew to nearly 20,000 acres by Friday.

The gusty winds that helped spread multiple wildfires gradually subsided on Wednesday afternoon, but dry conditions mean less potent winds could still be dangerous. More strong winds are expected later Thursday.

Santa Ana winds are caused by strong high pressure over the Great Basin region of the West creating a pressure gradient that amps up winds through the mountains, foothills and sometimes valleys of Southern California. In this case, the winds are getting a major boost from a strong upper-level low pushing southward across the state.

At least five wildfires are ravaging Southern California, and the three largest have already killed at least five people, burned tens of thousands of acres and prompted the evacuation of an estimated 179,

With multiple wildfires and high winds impacting the greater Los Angeles area and other parts of southern California, local airports and many common tourist destinations are affected.

Forecasters warned Southern California could see a “life-threatening, destructive” windstorm this week, as powerful gusts and dropped humidity levels raise the risk for wildfires in parched areas still recovering from a recent destructive blaze.