(CNN) — About 20,000 residents are under mandatory evacuation orders after a Southern California fire, which authorities say was set intentionally, spread this week.

The Holy Fire started Monday in the Cleveland National Forest and has so far destroyed 12 structures, according to fire authorities.

A man has been arrested in connection with the fire that is wreaking havoc near the border between Orange and Riverside counties, which are among the most populous counties in California.

The blaze had burned more than 9,600 acres as of Thursday morning, an almost 50% increase from the report the night before.

It remains only 5% contained, according to the national forest’s Twitter feed. Schools have been closed in Menifee, Perris and Lake Elsinore.

“Firefighters continue to battle the blaze around the clock,” the national forest tweet said. “We expect favorable weather conditions this weekend to help these efforts.”


Although it’s not the largest fire burning in the state, there are growing concerns about how it could affect residential communities — including Lake Elsinore. Some small communities in Riverside County are under mandatory evacuation orders affecting about 7,000 residential structures, according to authorities.

Forrest Gordon Clark, 51, was being held at the Orange County Jail on Wednesday on suspicion of two counts of felony arson, a count of felony threat to terrorize and misdemeanor resisting arrest, the national forest said via Twitter.

He is being held on $1 million bail and expected in court Thursday.

The charges being leveled could carry a life sentence, said Susan Schroeder of the Orange County District Attorney’s Office.

“Arson is a terrible crime that destroys dreams,” she said in a press conference Wednesday.

Witness statements, physical evidence and burn patterns connected the man to the fire, said Shane Sherwood with the Orange County Fire Authority.

Volunteer Fire Chief Mike Milligan told the Orange County Register that Clark was screaming in the community and sent an email that said “this place will burn” last week.

Before he was arrested, Clark told a cameraman he was asleep when the fire started and had no idea how it began.

“Who would go out with low humidity, and high wind and highest heat temperatures this time of year and intentionally set the forest on fire?” asked Orange County Supervisor Todd Spitzer during Wednesday’s press conference.

An excessive heat warning for the fire area has been issued with temperatures higher than 100 degrees.

“We know this district burns, but it should never burn because of an intentional act,” Spitzer said. “This shouldn’t be called the Holy Jim Fire, this should be called the Holy Hell Fire.”

Spitzer added that his constituents are “scared” and “fleeing their homes.”

“They’re leaving property behind, they’re putting everything they can in the back of their cars as quickly as possible.”

Fire officials warned residents to heed evacuation orders.

“Even if you’re miles away, you want to be prepared if you’re near the fire area or in an environment that can burn,” said Thanh Nguyen with the SoCal Team One Fire Management Team, who suggested having a packed bag ready to go.

Top three largest fires in California

Firefighters in California are battling 15 large fires.

The largest fire in California history is the Mendocino Complex Fire, which consists of the Ranch and River fires — in Northern California. That blaze had burned burned more than 304,000 acres and injured two firefighters, as of Thursday morning.

The second biggest fire is the Carr Fire in Shasta County, also in Northern California. The deadly fire has been burning for more than two weeks and consumed 177,450 acres as of Thursday morning. It has killed seven people, including two firefighters, and destroyed almost 1,100 homes.

The third largest is the Ferguson Fire, near Yosemite National Park, scorching more than 95,000 acres. That fire has lasted more than three weeks and killed two people.

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