Santa Ana winds occur when air flows west from a region of high pressure over the dry Great Basin to lower pressure off the California coast, According to Accuweather. As that cool interior air flows over and through mountain passes, it accelerates, sinks and compresses.

Santa Ana winds in Southern California are often-fierce winds that topple power lines and trees and can turn a spark into a raging wildfire.

The Palisades, Eaton, and Hurst fires covered more than 5,600 acres of Southern California as of Wednesday morning. Tens of thousands were under mandatory evacuation orders but the fires increased in size overnight, helped by the blustery Santa Ana winds.