Red alert in force: Emergency evacuation, flames will go "nuclear" PHOTO/VIDEO

The fire, named Hughes, started Wednesday morning in the Castaic Lake area of ​​Los Angeles County and quickly burned 3,407 acres.

Evacuations with warnings of "imminent threat to life" are underway, while much of Southern California is under a red alert for extreme fire risk from strong, dry winds.

The number of people under the evacuation order has not been specified, but the community of Castaic has about 18,600 inhabitants.

Firefighters from the Angeles National Forest are engaged in extinguishing the fire, the US Forest Service said, announcing that the entire 700,000-acre park in the San Gabriel Mountains was closed to visitors.

The cause of the fire is under investigation. Photos show plumes of smoke rising from the area as firefighters try to contain the blaze.

"That fire is going to escalate to a massive scale. We already know what fuel in that area can do, and the wind is going to make it even worse," Pierce County fire coordinator Jacob Weigler told the New York Post.

The fire quickly spread to nearly 20.72 square kilometers of trees and brush, creating a huge plume of dark smoke near Castaic Lake, a popular recreation spot about 40 miles from the devastating Eaton and Palisades fires, which are now in their third week.

Interstate 5 closures, the main north-south route, were put in place as tongues of flame swept across the hills and descended into inaccessible gorges.

Crews on the ground and firefighting planes were trying to keep the wind from moving the fire toward the more densely populated communities in the foothills of Castaic, home to about 18,000 people.

At least three schools were evacuated as a precaution, the California Highway Patrol said.

Meanwhile, to the south, Los Angeles officials braced for possible rain, while some residents were allowed to return to the burned areas of Pacific Palisades and Altadena. Windy weather is expected until Thursday.

"We're going to face another wave of critical fire conditions across Southern California," National Weather Service meteorologist Todd Hall said Wednesday morning. "This sounds like a broken record."

Los Angeles Mayor Karen Bass issued an executive order to expedite cleanup in affected areas and mitigate the environmental effects of pollution caused by the fires.

The Eaton Fire, which has burned 14,021 acres east of Los Angeles, was 91% contained, while the larger Palisades Fire, which has burned 23,448 acres on the west side of Los Angeles, was 68% contained Wednesday.

Since both fires broke out on Jan. 7, they have destroyed an area nearly the size of Washington, D.C., killed 28 people and damaged or destroyed nearly 16,000 structures, the California Fire Department (Cal Fire) said.

AccuWeather, a private weather service, estimates damage and economic losses at more than $250 billion.

President Donald Trump said California officials could have stopped the LA fires by "opening the valve" and releasing millions of gallons of water as the city burned.

"Los Angeles has tremendous amounts of water available," Trump said at a press conference on Tuesday. "All they have to do is open the valve."

California Governor Gavin Newsom disputed the claims, telling DailyMail.com that "Trump either doesn't know how water is stored in California or is deliberately misleading the public."