Colder weather is helping firefighters contain a third of California’s massive blaze

CHICO, Calif. (AP) — Fire crews battling California’s biggest wildfire this year have contained a third of the blaze, helped in part by cooler weather, but a return to triple-digit temperatures could allow it to grow , fire officials said Sunday.

Cooler temperatures and increased humidity have given firefighters “a great opportunity to make some good progress” on the blaze in the Sierra Nevada foothills, said Chris Vestal, a spokesman for the California Department of Forestry and Fire Protection.

The Park Fire has burned 627 square miles (1,623 square kilometers) since it ignited on July 24, when authorities said a man pushed a burning car into a ditch in Chico and then fled. The fire was 30 percent contained as of Sunday.

The massive fire burned an area larger than the city of Los Angeles, covering about 503 square miles (1,302 square kilometers). It continues to burn through rugged, inaccessible and steep terrain with dense vegetation.

The fire’s northward push has brought it into the rugged lava rock landscape surrounding Lassen Volcanic National Park, which has been closed due to the threat. Inhospitable terrain remains one of the biggest challenges for firefighters.

“The challenge with that is we can’t use our heavy machinery like bulldozers to go through it and cut a line right through it,” Vestal said.

“On top of that, we have to put in human beings, our hand crews, to remove those fuels, and some of that terrain isn’t the best for people hiking, so it takes a lot of time and work extremely hard,” he said. added.

The fire has destroyed at least 572 structures and damaged another 52. At least 2,700 people in Butte and Tehama counties remain under evacuation orders, Veal said.

After days of smoky skies, clear skies on Sunday allowed firefighters to send helicopters and other aircraft to help battle the blaze as temperatures soared above 100 degrees Fahrenheit (about 38 degrees Celsius).

“The fire is in a good place because of the weather conditions that we’ve had the last couple of days, but we still have to worry about the weather that we have and the conditions that are going to be there now for the next five or six days, Veal said.

The Northern California wildfire is one of 85 large wildfires burning in the West.

In Colorado, firefighters made progress Sunday against three major wildfires burning near heavily populated areas north and south of Denver. Many residents evacuated by the fires have been allowed to return home.

The Jefferson County Sheriff’s Office is investigating a fire that threatens hundreds of homes near the Colorado town of Littleton as arson.

About 50 structures were damaged or destroyed, about half of them homes, by a fire near Loveland. And one person was found dead in a house fire west of Lyons.

Scientists say extreme wildfires are becoming more frequent and more destructive in the western US and other parts of the world as climate change warms the planet and droughts become more severe.

In Canada, a 24-year-old firefighter battling a fire in Jasper National Park was killed by a falling tree on Saturday, the Royal Canadian Mounted Police said.

The Calgary firefighter, whose name has not been released, was battling a blaze north of Jasper, an Alberta town that was half-destroyed last month by a fast-moving blaze.