About 1,500 people have been evacuated from the Bear Valley area and the American Red Cross is providing shelter and aid to those evacuees at Panguitch High School in Parowan.
Sizzling heat is exacerbating the fire risks out West, where tired crews have been battling blazes in Utah, Nevada, Oregon and California.
Smoke visible in Routt County Tuesday can be attributed to the Brian Head Fire in southwestern Utah, according to Kevin Thompson, Routt County National Forest fire management officer.
The Brian Head Fire in Utah is the nation's largest largest wildfire and firefighters are still struggling to gain control of it.
The blaze broke out late Monday afternoon and quickly grew to almost 1.5 square miles, the California Department of Forestry and Fire Protection said.
Crews in California, meanwhile, are allowing people back to their homes near Santa Clarita as traffic starts moving again on a Los Angeles County freeway.
"Horse Valley will be an area of concern (Monday), but crews have begun to prepare for this using dozers and retardant dropped from air tankers to establish indirect firelines", the town of Brian Head said on its Facebook page.
The fire erupted on June 17 near the ski resort of Brian Head, Utah, about 30 miles northeast of Zion National Park, and spread quickly as high winds drove flames into dense forests, threatening homes in nearby communities. That blaze broke out late Monday afternoon and grew to about 500 acres in just a few hours, according to the California Department of Forestry and Fire Protection.
Authorities issued mandatory evacuation orders for residents in some areas threatened by the blaze, though it was not clear how many people were affected, the Los Angeles County Sheriff's Department said.
Another California wildfire, sparked by a traffic accident on a remote stretch of highway 80 miles (129km) east of Los Angeles, has grown to almost two square miles (more than 500 hectares) in just a few hours. The blaze was 20 percent contained at midday Tuesday.
In New Mexico, Gov. Susana Martinez ordered flags to fly at half-staff in honor of a volunteer firefighter who died from injuries suffered while battling a brush fire in eastern New Mexico last week.
"People are not being careful enough", he said, noting that several other human-caused fires had broken out over the weekend.
Nearly 300 miles north of the Frye Fire, the Goodwin Fire in Mayer, Arizona gained ground on Tuesday night, authorities said.