INDIAN FALLS, California - Flames racing through rugged terrain in northern California destroyed multiple homes on Saturday as the state's largest wildfire intensified and numerous other blazes battered the US West.

The Dixie fire, which started on July 14, had already leveled more than a dozen houses and other structures when it tore through the tiny community of Indian Falls after dark.

Fire officials said the blaze has charred more than 73,200 hectares in Plumas and Butte counties and was 20 percent contained.

The fire was burning in a remote area with limited access, hampering firefighters' efforts as it charged eastward, officials said. It has prompted evacuation orders in several small communities and along the west shore of Lake Almanor, a popular getaway.

The southern Oregon's Bootleg fire, the nation's largest wildfire, was nearly halfway surrounded on Saturday as more than 2,200 crew members worked to corral it in the heat and wind. Authorities said the growth of the blaze had slowed, but thousands of homes remained threatened on its eastern side.

"This fire is resistant to stopping at dozer lines," said Jim Hanson, fire behavior analyst, in a news release from the Oregon Department of Forestry. "With the critically dry weather and fuels we are experiencing, firefighters are having to constantly reevaluate their control lines and look for contingency options."

In California, Governor Gavin Newsom has declared a state of emergency in four northern counties because of wildfires that he said were causing "conditions of extreme peril to the safety of persons and property". The proclamation opened the way for more state support.

Climate change

Such conditions are often from a combination of unusual random, short-term and natural weather patterns heightened by long-term, human-caused climate change. Global warming has made the West much warmer and drier in the past 30 years.

On Saturday, Montana Governor Greg Gianforte said that fire crews from California and Utah headed to his state. Five firefighters were injured on Thursday when swirling winds blew flames back on them as they worked on the Devil's Creek fire burning in rough, steep terrain near rural Jordan town in the northeast part of the state.

Elsewhere in California, the Tamarack fire south of Lake Tahoe continued to burn through timber and chaparral and threatened communities on both sides of the California-Nevada state line.

Heavy smoke from that blaze and the Dixie fire lowered visibility and at times may ground aircraft providing support for fire crews. The air quality south of Lake Tahoe and across the state line into Nevada deteriorated to very unhealthy levels.

More than 85 large wildfires were burning around the country, mostly in western states, and they had already burned more than 553,000 hectares.

AGENCIES VIA XINHUA