But they are still bracing for winds that could cause flare-ups, and for a third day, evacuation orders remained in place for 250 upscale homes northeast of Park City. The mountain town is home to world-renowned ski resorts that hosted many events in the 2002 Winter Olympics.
"We have a lot of pockets of green in there that are still burning that are a threat to the homes," said Utah fire official Mike Eriksson, standing in front of a smoldering canyon dotted with big houses. "It's still just not safe."
Working in 90-degree heat, hundreds of firefighters set back fires and bulldozed lines Thursday to contain the 3.1-square-mile fire. Above them, helicopters made dozens of flights to and from a nearby lake to douse the flames with fire retardant. Commanders repositioned fire engines and crews to protect 250 threatened homes, some along a golf course in the gated community of Promontory.
The Rockport Fire started Tuesday afternoon by a lightning strike that shook a nearby convenience store and ignited a fast-moving blaze that quickly destroyed a dozen homes.
Two more houses were lost Wednesday, but firefighters saved 22 others from burning in the same area, said Summit County District Fire Warden Bryce Boyer. No houses have been burned Thursday, and the fire has remained calm thanks to calm winds.
The blaze was about 25 percent contained, with fire officials hopeful that figure can reach 50 to 60 percent by Friday morning.
The burned houses are mostly upscale homes built on picturesque mountainsides. The blaze has come dangerously close to dozens of other houses built along steep hillsides with vaulted ceilings and large picture windows visible from roadsides below.
The biggest and most expensive of the evacuated homes, in Promontory, were the safest so far, but those homeowners are also barred from returning home. The Summit County Sheriff's Office offered to escort people to threatened homes for emergency supplies, pets or medicine.
The wildfire has placed many families in limbo, said Ian Jasenovic, who had just minutes to leave with his wife and their twin 4-year-olds. They grabbed the family's cats and photo albums, and later learned their house had been spared - for now.
"You feel displaced. You are out of your comfort zone," said Jasenovic, who works from home and left his laptop.
Most of the destroyed houses were year-round residences, said Claudia McMullin, chairwoman of the Summit County Council.
"It's very upsetting," she said. "I'm please there is no loss of life and I'm very sad for the loss of property."
Residents have always known wildfires are a threat, she said.
"It's a mountain desert environment and we are the second or third year of a drought," McMullin said. "So we talk about fire all the time."
The Park City-area fire was among 34 major fires burning 1,100 square miles across the West, including Alaska, officials said Thursday.
Two small wildfires ignited by lightning Wednesday at Yellowstone National Park didn't threaten visitors or structures, officials said. Yellowstone has two other small fires, and several others were burning in Bridger-Teton National Forest in western Wyoming.
It's unusual for Alaska to have six major fires burning this late in the season, but weather there has been warm and dry, said Don Smurthwaite, a spokesman for the National Interagency Fire Center in Boise.
One of the fires burning in Alaska's interior has consumed 87 square miles. The Alaska Fire Service warned of "record-setting fire spread potential" as flames feasted on boreal spruce and tussock tundra fuels.
The mountain region where the Utah blaze burns is bone dry, too, but having a reservoir less than half a mile away from the southern edge of the fire has been a boon for firefighters.
"They can get a lot of water up on the mountain very quickly," Eriksson said.