HAILEY, Idaho — Fire crews on Saturday faced another challenging day battling a rapidly growing wildfire burning closer to two posh, central Idaho resort communities, while other fires raged on in the West.

In northern Utah, several manufactured homes were destroyed when the Patch Springs Fire raced through the community of Willow Springs late Friday, jumping a state highway and fire lines, authorities said.

As of early Saturday, officials said that blaze had burned about 33,000 acres, or more than 50 square miles. It was estimated at 20 percent contained.

Idaho’s Beaver Creek Fire, meanwhile, grew by 15 square miles late Friday and early Saturday, to 144 square miles. Overnight, flames moved closer to homes and subdivisions in the mountains west and north of the communities of Hailey and Ketchum, and the Sun Valley Resort.

So far, authorities have issued mandatory evacuations for 1,600 residences in this smoke-shrouded valley. More homeowners, along with the growing camp of firefighters and support staff, could be asked to move Saturday depending on fire activity, fire officials said.

The blaze was started by lightning Aug. 7. It expanded significantly Friday, burning through tinder-dry brush and timber in the mountains west of the towns. Efforts Saturday were focused on protecting homes and structures in the gulches and foothills just west of Hailey and Ketchum.

Crews also planned to target erratic, wind-driven fire growth in one area north of Ketchum and two locations west of Hailey.

For now, that battle is taking place on the ground because heavy smoke has grounded air tankers capable of dumping retardant and water on the perimeters.

Fire managers and more than 700 firefighters are bracing for another dose of hot temperatures and afternoon wind gusts up to 30 mph that could move flames closer to homes. Hundreds of more firefighters will be arriving Saturday as other fires in Idaho and other western states die down.

“This fire is consuming everything,” fire spokeswoman Madonna Lengerich said. “The fire is so hot it’s just cremating even the biggest trees.”

The tight valley that bookends these communities — and serve as vacation getaways for celebrities like Arnold Schwarzenegger and Tom Hanks — is covered in thick smoke.

Downtown retail and dining districts, normally buzzing this time of year with tourists and summer residents, are quiet, and some merchants haven’t even bothered to open for Saturday breakfast and lunch.

Ketchum, with a population of 2,700, and Sun Valley, with 1,400 people, also are under “pre-evacuation orders.” Authorities have told them to be ready to leave if necessary.

On Friday, Sun Valley Ski Resort officials turned on water cannons, used for wintertime snowmaking, to protect lodges on the mountain and ski lift equipment.

In addition to the government firefighters, some private insurers have sent in their own crews to provide structural protection for homes with values that can stretch into the millions of dollars, Blaine County Sheriff Spokeswoman Bronwyn Nickel said.

“There are private engines that insurance companies have sent in,” she said. “They’re on site. They’re working with our local firefighters and law enforcement.”

In Utah, the Patch Springs Fire burning in Tooele County jumped Highway 199 as it burned through community of Willow Springs. That fire was sparked by lightning Aug. 10.

Meanwhile, firefighters report progress on a fire burning near Park City, Utah.

The Rockport broke out Tuesday and has destroyed eight homes. Officials say it has burned about 1,900 acres and was 58 percent contained early Saturday.