Strong Santa Ana winds are hitting fire-ravaged Los Angeles on Friday morning, but the winds will relax later in the day and the red flag warning will end Friday night.

Santa Ana winds are common in Southern California during cooler months. Here’s a look at the often-fierce winds that topple power lines and trees and can turn a spark into a raging wildfire.

The devastating fires that have killed at least five people and forced the evacuations of tens of thousands of residents across the Los Angeles region are driven by Santa Ana winds that blow from the deserts of interior California and Nevada out to the Pacific Ocean.

Red Flag Warnings remain in effect through Friday evening for much of Los Angeles and Ventura Counties, the National Weather Service said.

By the time the winds get to the point where the Eaton Fire broke out in Altadena on Jan. 7, it’s not uncommon for them to have less than 5 percent relative humidity, meaning essentially no moisture at all.

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.

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,

The Santa Ana winds are blustery, dry, and warm and can result in massive damage. These winds could boost the danger of a wind-driven fire if they occur during wildfire season. Three major wildfires in the Los Angeles area are being driven by one of the most powerful Santa Ana winds in years.

When coastal California becomes news with the report of multiple wildfires, especially during fall and winter, there is usually a mention of Santa Ana winds. These winds are the result of strong high pressure farther east in the inter-mountain western region,