A man was arrested on Thursday on suspicion of starting a wildfire that forced thousands to flee their homes in a fast-moving blaze that is the largest in California so far this year.

Butte County District Attorney Mike Ramsey said in a statement that the man, Ronnie Dean Stout II, was jailed without bond on a Butte County judge’s warrant after he was identified as the person seen pushing a flaming car into a gully on Wednesday afternoon.

The vehicle spread flames that caused what is being called the Park Fire, which exploded overnight from about 1,400 acres on Wednesday near Chico, California, to about 125,000 acres on Thursday afternoon in northern California about 80 miles north of the state capital Sacramento.

The 42-year-old suspect was detained by arson investigators with the state California Department of Forestry and Fire Protection, or Cal Fire, along with police.

His arraignment is set for Monday, according to Ramsey, who did not specify what type of arson charge the man might face. A spokesperson for the Butte County District Attorney’s Office did not immediately respond to a Reuters request for more details.

The Park Fire was only 3 percent contained on Thursday afternoon and the largest in the state so far this year, Cal Fire said. No injuries were reported.

More than 4,000 people were evacuated in Butte County and the city of Chico, said Megan McMann, a spokesperson for the Butte County Sheriff’s Office.

The largest fire now burning in the United States, Oregon’s Durkee Fire, has burned at least 268,000 acres, threatened multiple small towns, scorched ranch land and killed cattle by the hundreds, local media reported.

High winds, with gusts of 60 miles mph (97 kph) along with lightning strikes on Wednesday and overnight could fan the flames, said Marc Chenard, a forecaster with the National Weather Service in College Park, Maryland.

The fire, about 100 miles northwest of Boise, Idaho, was 20% percent contained on Thursday afternoon. More wind was forecast and lightning possible.

“There is zero percent chance of rain in the forecast for the region,” Chenard said.

Smoke from fires in western Canada and the Pacific Northwest is blamed for hazy skies and unhealthy air from the Rocky Mountains to Chicago, weather reports said. Denver had the worst air quality in the U.S. and ranked the 22nd worst in the world, according to IQAir, a group that tracks air pollution across the globe.

The air could be clearing later on Thursday as a high-pressure ridge rolls in bringing clearer skies, according to weather reports.

Scientists and environmental advocates have long called for global leaders to phase out and end the reliance on fossil fuels to prevent catastrophic effects of climate change, including worsening wildfires.