The Holy Fire - named for Holy Jim Canyon where it began is one of nearly 20 blazes across California. Authorities have issued mandatory evacuation orders and one person has been arrested in connection with one of the blazes.
Authorities battling massive wildfires in large swathes of California issued mandatory evacuation orders and health warnings Friday over the worsening air quality as the flames grew ever closer to populated areas.
After almost a month of wildfires, the National Weather Service warned that satellite images showed "widespread smoke" drifting from the fires into western and central Canada before heading back south in the US Northern Plains.
The Kaibab National Forest service in neighboring Arizona warned that "wildfires across the West are creating regional haze."
But it was northern California where most air quality alerts were being issued, with warnings of "unhealthy conditions" for vulnerable groups such as the very young and old.
The Holy Fire, which broke out on Monday in Holy Jim Canyon in Orange County southeast of Los Angeles, has already destroyed 12 structures and was only 5 percent contained as of Friday.
The fire grew to nearly 77 square kilometers after nearly doubling in size overnight.
More than 21,000 people and 7,400 homes have been evacuated in and around the city of Lake Elsinore, where flames and billowing smoke rose into the sky at the edge of the city of 60,000 near the Santa Ana Mountains.
Many schools have been forced to close, and more evacuation orders were being issued.
Three firefighters suffered minor injuries battling the flames, which have charred more than 18,000 acres (7,280 hectares). Governor Jerry Brown has declared a state of emergency for the area.
The Holy Fire was one of several blazes burning across California that have displaced tens of thousands. Smoke from the western wildfires has reached the East Coast and beyond, the National Weather Service has said.
Erratic court appearance
Forrest Gordon Clark, 51, who owns a cabin in Holy Jim Canyon, was arrested earlier this week after a standoff with police and charged with arson, making criminal threats and resisting arrest.
He is accused of deliberately starting the latest fast-moving Holy Fire and faces life in prison if convicted of arson and other charges.
The head of the Orange County team fighting the Holy Fire said the blaze had started near Clark's cabin in Jim Canyon.
Prosecutors say Clark started the fire, which is only five percent contained, with the intention of causing damage to others and burning a forest. The blaze has razed a dozen properties so far.
He has also been charged with threatening neighbors - one of whom lost his cabin in the fire - and resisting arrest. He faces sentences ranging from 10 years to life imprisonment.
Mike Milligan, the local volunteer fire chief who owns a cabin near Clark's, told The Orange County Register that Clark had long-running feuds with neighbors in the area.
Milligan said that Clark had recently sent him an email warning, "this place will burn."
Before his arrest, Clark told a reporter he had nothing to with the fire.
"I was asleep. I had two earplugs in," he told the reporter. "I woke up and my stuff was all on fire," he said. He also claimed he had been threatened by the MS-13 gang.