By Liya Cui and Rich McKay

(Reuters) – A fast-moving wildfire killed at least one person in the Rocky Mountain foothills of Colorado, one of a handful of blazes burning across the state, while thousands of firefighters in California struggled to contain the largest fire in the country.

The individual killed in the Stone Canyon Fire, burning about 20 miles north of Boulder, Colorado, was found on Wednesday in one of five homes destroyed near Rocky Mountain National Park, officials said.

“We did also today discover human remains in one of the residences,” Boulder County Sheriff Curtis Johnson told the media. “So, I can confirm for you that we do have one fatality associated with the fire.”

Johnson did not provide details on the individual’s identity.

The Stone Canyon Fire, near Lyons, a community of about 2,000, has burned more than 1,500 acres since Tuesday afternoon. It was 20% contained as of late Wednesday, the Boulder Office of Disaster Management said in a statement. About 2,000 people were evacuated from Lyons and nearby communities.

Colorado Governor Jared Polis called in the Colorado National Guard to assist with the recovery. Since Tuesday afternoon, dry conditions and high temperatures enabled the fire to spread quickly through timberland.

The Stone Canyon Fire is one of multiple fires that have ripped Colorado’s Front Range mountains this week, prompting further evacuations.

The Alexander Mountain Fire is the largest, having burned over 7,000 acres since Monday. It was 1% contained since Wednesday night, according to the U.S. Forest Service.

Across the country, more than 29,000 firefighters and support personnel are fighting 93 large wildfires, encompassing more than 2 million acres, according to the National Interagency Fire Center.

In California, the Park Fire has burned more than 600 square miles (1,550 square kms) as of Thursday morning, an area bigger than the city of Los Angeles, state fire officials said.

It is the fifth largest fire in the state’s history and could soon become the fourth. Nearly 6,000 firefighters battled the blaze in a wilderness area in the state’s Central Valley, about 90 miles (145 km) north of Sacramento, the capital.

The fire has destroyed 437 houses and other structures and damaged 42 as of Thursday morning, the California Department of Forestry and Fire Protection, or Cal Fire, reported.

The man charged with starting the fire, allegedly by pushing a flaming car down a Butte County gully last week, was formally charged with arson on Monday, but awaits additional charges, officials said.

Over the last few days the weather had been cooler, helping firefighters, Cal Fire spokesman Jeremy Hollingshead said. But temperatures are expected to climb today and could reach 104 F this weekend.

“We had an advantage for the last couple days with cooler temperatures. But now that changed,” Hollingshead said. “It means the fuels of grass and timber are getting dryer and hotter earlier in the day. The fire will burn hotter and quicker.”

He said access over rough, wilderness terrain with few roads makes it hard for firefighters and equipment to get at the fire lines, sometimes taking two to three hours to arrive at the scene.

(Reporting by Liya Cui in New York and Rich McKay in Atlanta; Editing by Frank McGurty and Leslie Adler)