On a hot Wednesday in July, Ronnie Dean Stout II stood next to a smoking Toyota Yaris at a swimming hole in Chico, California, and watched the flames grow, authorities allege. He made no effort to put out the fire and then pushed the vehicle over a 65-foot embankment, according to a witness account from court documents.
The car rolled into a ravine filled with dry vegetation, which the witness saw “explode” into flames, according to the lawsuits.
The temperature that day was well over 40 degrees and it was windy – “red flag” conditions that were ripe for fire. The fire spread at breakneck speed. In just 48 hours, the Park Fire had destroyed more than 130 structures, burned 175,000 acres and forced thousands to evacuate, the court said.
Stout has denied pushing the car, the prosecutor said, and he has pleaded not guilty to arson. A public defender representing Stout did not respond to a request for comment.
The Park Fire was the fourth largest in California history, burning 430,000 acres. It set a state record for acres burned in an alleged arson.
“There has been no arson-related fire that has ever reached this magnitude,” said Gianni Muschetto, chief of police for the California Department of Forestry and Fire Protection. “That will be something of historical significance.”
In total, just over 1 million acres have burned in California so far this year, and nearly half were the result of fires reportedly started by arsonists, according to fire officials and an NBC News review of state incident data .
About 10% to 15% of California wildfires are caused by arson each year – and 2024 appears to be in line with the trend. But as climate change causes temperatures to rise, fire seasons to lengthen and droughts to intensify, intentionally set fires have more opportunity to take off and grow.
That has led to more than 477,000 acres burned this year due to suspected arsons — by far the most since 2014, when 98,259 acres burned due to arson, according to Cal Fire.
Muschetto said fires ignited by arson pose the greatest risk when drought or other effects of climate change have caused wood to dry out.
“Then it’s more likely that those fires could grow bigger more quickly and damage or burn homes — or hopefully not, but possibly — and injure or kill people who can’t escape because the fire eventually grows,” he said.
Additionally, he added, California’s wildfire season is lasting longer than it used to. The state’s southeastern desert basin added 61 additional fire days between 1973 and 2022, according to the nonprofit Climate Central.
“That just means more opportunities to start wildfires year-round,” Muschetto said.
This week, parts of California were wilted by a record October heat wave. Temperatures in the Los Angeles area were expected to become “dangerously hot” off the coast, with temperatures reaching 105 degrees in some regions on Saturday, according to the National Weather Service.
Jeffrey Prestemon, a researcher at the US Forest Service’s Southern Research Station in North Carolina, said arson also poses an acute risk because fires started that way tend to cause more damage per acre than fires caused by lightning or other factors.
“They’re often located where people live, where there are structures,” Prestemon said.
Given that, he said, “an arrest can have a big payoff.”
Prestemon has studied wildfires in Florida, Spain and other locations. He and other researchers found in one study that the arrest of a single arsonist in a particular region of Spain correlated with a decrease of nearly 140 wildfires in that area the following year.
“What we suspect: it’s mainly a serial effect, it’s one person setting multiple fires in a short period of time, usually spread over several days, a week or two weeks,” Prestemon said. “If they are not caught, they will repeat this kind of serial episode.”
Prestemon added that arrests could deter other arsonists.
This year, Cal Fire had arrested 91 people on suspicion of arson in California by the end of August, Muschetto said. The number seems to follow normal trends.
Wildfire arson has not been well studied, but researchers in the US, Europe and Australia have narrowed the profile of typical perpetrators. Arsonists of wildfires are usually men, often young. Many set multiple fires.
“There is a good chance that they will cause fires repeatedly,” said Janet Stanley, an honorary associate professor at the University of Melbourne in Australia. “People who for some reason have a psychological need in a fire will do it many times, and often they don’t get caught until they’ve done it multiple times.”
In California, Muschetto attributed fluctuations in wildfire arson rates to fire risk levels and the likelihood that the landscape would burn.
Cal Fire has counted between 182 and 386 arsons annually since 2014, with the numbers being roughly consistent relative to the total number of fires. However, the actual number of fires caused by arson is likely higher than the official number because investigators cannot always determine how a fire started. The causes of more than 320 fires in 2023 remain unknown.
Wildfire arsons can also be difficult to prosecute for similar reasons, experts say. Compared to urban arson, these crimes often produce less physical evidence, said Daniel Fox, a prosecutor with the Riverside County District Attorney’s Office who has handled wildfire arson cases.
“It takes so much less to get the fire going and for it to become monstrous when you’re talking about wildland than it would take for me to set fire to a car or the side of someone’s house,” Fox said.
That’s especially true in the rural parts of his province, Fox added, where the landscape is so arid that he joked that even a sideways glance at the grass can “turn into flames.”
Muschetto said Cal Fire investigators are trained to identify wildfire patterns and where a fire started, then look for any remnants of an ignition source.
“It could be something as small as a match head, that’s all that’s left. You might not find anything if it’s completely consumed by a fire,” Muschetto said.
This can make investigators dependent on witness reports and circumstantial evidence. Muschetto said the increase in the use of security cameras, smartphones and satellite tracking devices in rural areas has helped Cal Fire solve more cases over the past 10 to 20 years.
But even when things go well for prosecutors, victims of arson-ignited wildfires rarely recover, Fox said.
He led the prosecution of Brandon McGlover, who set several fires that led to the 2018 Cranston Fire, which burned more than 13,000 acres near Idyllwild, California, and destroyed several homes.
Investigators were able to link McGlover’s plausible movements to several fires that day, Fox said. They had eyewitness testimony connecting McGlover’s car to an area where a fire started, traffic camera video, surveillance video and cans of WD-40 discovered in his car.
Prosecutors reached a settlement and McGlover was sentenced to more than twelve years in prison and ordered to pay restitution to the victims. But Fox said it is unlikely that the people who lost property will have their full losses covered through insurance or refunds.
“The reality is there is no real mechanism to compensate them,” Fox said. “His name was not Bezos or Rockefeller and he was going to prison for a long period of time.”
Stout, the suspect in the Park Fire, was arrested on July 25, a day after the fire started, and charged with “arson of an occupied building or property.” If convicted, he faces 25 years to life in state prison.
Butte County District Attorney Mike Ramsey said in an email that Stout has said the witness account of his alleged actions is inaccurate.
Stout is being held in the Butte County Jail pending trial. His next court appearance is Oct. 17, when a date is expected to be set for a preliminary hearing.
This article was originally published on NBCNews.com