Homes and properties were destroyed Saturday as the Dixie Fire continued to rage in Northern California, officials in the state said.
The blaze, 20 percent of which had been contained Saturday, has charred more than 181,000 acres in Plumas and Butte counties, consuming more than a dozen homes and properties, as it has torn through the region, officials said.
The raging fire and heavy smoke have led to evacuation orders in several communities and along the west shore of Lake Almanor.
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Elsewhere, the Tamarack Fire continued to burn through timber and threaten communities south of Lake Tahoe on both sides of the California-Nevada border. The air quality in the area has deteriorated to very unhealthy levels.
California Gov. Gavin Newsom declared a state of emergency for four northern counties as flames spread Friday, saying the wildfires were causing "conditions of extreme peril to the safety of persons and property."
Many fires are burning across the U.S. West, where extremely dry conditions and heat waves tied to climate change have made them difficult to fight.
Nearly 90 large fires had scorched more than 1.4 million acres across 13 states as of Saturday, according to the National Interagency Fire Center.
Oregon's Bootleg Fire — the country's largest inferno — was nearly halfway surrounded Saturday as more than 2,200 firefighters made progress corralling it, officials said.
There has been so much smoke from the fires in the West that it is helping firefighters gain ground on the Bootleg Fire by blocking sunlight, officials said Saturday.
"It's called 'smoke shading,' and it's basically put a lid on the lower atmosphere for now, blocking sunlight and creating cooler, more stable surface conditions," said Eric Schoening, a meteorologist with the National Weather Service in Salt Lake City. The phenomenon, however, is unpredictable, and the area was still under red-flag warnings over the weekend.
While the growth of the fire finally slowed, thousands of homes in southern Oregon remained threatened. Extreme fire behavior and an unstable atmosphere created by the Bootleg Fire formed a tornado in the area last weekend.
"With the critically dry weather and fuels we are experiencing, firefighters are having to constantly reevaluate their control lines and look for contingency options," Jim Hanson, a fire behavior analyst, said Saturday in a news release from the Oregon Forestry Department.
Also Saturday, fire crews from California and Utah headed to Montana, Gov. Greg Gianforte announced, after five firefighters remained hospitalized after a thunderstorm blew a lightning-caused Montana wildfire back onto them. The extent of their injuries was still unknown.
Another high-priority wildfire, the Alder Creek Fire in southwest Montana, had charred over 6,800 acres and threatened hundreds of homes. It was only 10 percent contained Saturday night.
Firefighters also battled blazes Saturday in north-central Washington, where hundreds of homes are under threat and air quality conditions continue to deteriorate.
While a chance of scattered thunderstorms over the weekend could offer some respite across California, Utah, Nevada, Arizona and other Western states, forecasters warned that dry storms that produce little rain but a lot of lightning can spark new blazes.
The smoke from the fierce fires has been carried all the way across the continental U.S. to the East Coast, where air quality alerts were issued.