Park Fire blew up

'All the factors came together': How California's Park Fire blew up so fast

By Amy Graff

In a matter of three days, California’s Park Fire grew to a 350,012-acre monster that is consuming the bone-dry wilderness north of Chico, upending communities such as Cohasset and Forest Ranch and forcing thousands of people to leave their homes.

This is the largest wildfire California has seen so far this year, and the largest wildfire since the 963,309-acre Dixie Fire in 2021. California saw relatively quiet wildfire seasons in both 2022 and 2023, with just over 300,000 acres burned each year, compared with 2.6 million in 2021 and a historic 4.3 million in 2020. 

“The Park Fire reminds me of 2021 and 2020, and how the fires reacted those years,” said Brent Wachter, a fire meteorologist at the U.S. Forest Service’s Geographic Area Coordination Center in Redding. 

One reason the Park Fire, which is burning in Butte, Plumas, Shasta and Tehama counties, grew so big so fast is because the vegetation in this area is especially dense, and hasn’t been thinned out by a significant wildfire in recent history.

“That particular area got missed by the Dixie and Camp fires, so it’s an area that has more continuous timber,” Wachter said. “The vegetation is more dense, it doesn’t have big holes in it, and this allows the fire to get up into the canopy and that allows the embers to travel further.”

The devastating 153,336-acre Camp Fire killed 85 people and destroyed the town of Paradise, including 18,000 homes, business and other structures, in 2018. The southern edge of the Park Fire is only about 6.5 miles from Paradise, as the crow files. 

In 2021, the Dixie Fire devoured nearly 1 million acres across Butte, Plumas, Shasta, Lassen and Tehama counties. Craig Clements, director of San Jose State University’s Wildfire Interdisciplinary Research Center, told SFGATE on Friday that the Park Fire is burning toward the Dixie burn scar, and that’s expected to slow it down. 

Robert Foxworthy, a spokesperson for Cal Fire, said the Park Fire has passed through Cohasset and Forest Ranch, and these are communities that haven’t seen a big wildfire in recent history. He said portions of these communities have burned, though he doesn’t have specific information on where or the number of structures that were destroyed in each location.

“There are still areas that haven’t burned in those areas,” he said. “Until the fire is out, they’re still going to be areas that are threatened.”

The recent marathon heat wave that sent temperatures soaring across inland areas of California for two weeks is another factor contributing to the Park Fire’s explosion. The fire started Wednesday in upper Bidwell Park in Chico, which sits on the northeast edge of the Sacramento Valley, and has seen day after day of triple-digit heat this month. 

“The brush fuels that were fairly green a month or two ago are now dried out and highly flammable,” Wachter said. “That two-week heat wave in July just really put us over the top. We saw significant drying that brings vegetation down to a very flammable state.”

The high-risk fire weather on the actual day the Park Fire started, and that has continued through the week, is also part of what created this dangerous inferno. Winds have picked up in the afternoon this week, with isolated gusts up to 25 to 30 mph. Humidity levels have also been low with a dry air mass overhead. 

“All the factors came together to make this happen: super dry fuels, it had been really hot the day it started and in the days prior. … It was really dry and there was a lot of wind,” Foxworthy said.

The winds are forecast to pick up again Friday afternoon. More fire growth is expected. “Today is another day of wind, they’re expecting decent winds,” Wachter said. “I’m looking at it right now and there’s already a large column of smoke, it’s pretty early and we’re already seeing some pretty strong fire behavior. I would expect another dynamic day with some pretty intense fire behavior.”

The southerly winds have pushed the fire north of Chico and Bidwell Park into wilderness area, including the Ishi Wilderness in the foothills of the Cascade Range. This area is difficult for firefighters to access.

“If you’ve ever been and saw this area where the fire is burning, this is really nasty, inaccessible country and that makes a difference,” Foxworthy said.