Over 22 million people in Southern California are under a flood watch as a West Coast storm could slam burn scar areas, bringing potential mudslides, debris flows and excessive rainfall.

Evacuation warnings are now in place through Friday evening for the following burn scar areas: Canyon, Bethany, Eaton, Palisades, Hurst, Kenneth, Sunset, Lidia, Franklin and Bridge, according to Los Angeles County officials.

“Anyone in these areas should be ready to leave at a moment’s notice,” county officials said.

The storm will bring light to moderate rain for most of Friday, but the main threat for flooding will begin Friday night going into Saturday, with excessive rainfall — accompanied by lightning and some strong wind gusts — possible for some areas.

Beginning late Friday, evacuation orders will be in effect for the following burn scar areas: Canyon, Bethany, Eaton, Palisades, Hurst, Kenneth, Sunset, Lidia, Franklin and Bridge.

According to the Los Angeles Public Works, some streets may be “entirely blocked by debris” and some structures may be at risk depending on location.

These areas could see 1 inch of rain per hour, with rainfall between Friday and Saturday totaling 4 to 6 inches in the mountains of Santa Barbara, Ventura and Los Angeles Counties. Rain totals of 2 to 4 inches are forecast across much of Central and Southern California, including Los Angeles, Malibu and Santa Barbara.

Areas with the heaviest storms or at higher elevations could see 6 inches of rain or more.

A moderate risk for excessive rainfall and flash flooding is in place for Los Angeles and Santa Barbara areas, mostly for the heaviest rain which is expected on Friday night, Saturday morning and early Saturday afternoon.

A slight risk for excessive rainfall and flash flooding is in place across a large swath of Southern California, with scattered areas of flash flooding possible in these areas.

The heavy rain will mainly be occurring between 2 a.m. and 3 p.m. local time on Saturday, which is when the greatest risk in burn scar areas will be.

Flash flooding, mudslides and the risk of debris flows will quickly ramp up later on Friday into Saturday morning.

More rain is possible in these areas every day next week, with the threat of mudslides and debris flows continuing due to the already-saturated ground.

California Gov. Gavin Newsom announced on Thursday that emergency resources will be pre-deployed ahead of the storm to protect communities in the Los Angeles, Orange and Ventura counties from mudslides and debris flows.

On average, Los Angeles records 0.8 inches of rain the entire month of November, with the record being 9.68 inches in 1965. This storm beginning on Friday could likely be more than a November months’ worth of rain within a day for these areas.

ABC News’ Dan Peck contributed to this report.