Residents affected by the Rockport 5 fire must now stay out of their homes until at least 6 p.m. Thursday, The Salt Lake Tribune reported. The fire has burned 15 houses since it was started by a lightning strike Tuesday.
The fire was reported to be 25 percent contained Wednesday afternoon and had burned 2,500 acres. Firefighters escorted residents of the evacuation zone to their homes so they could get medications and other necessities.
News crews had to move out of a staging area in mid-afternoon when it was threatened by flames.
Evacuations had been ordered for 300 homes in communities and neighborhoods near the fire. Thousands of residents have lost power.
No injuries have been reported.
In Idaho, evacuations were ordered for three central mountain resort towns as fire crews battled two brutal wildfires.
Idaho's Elk Complex wildfire, engulfing 100,000 acres, or more than 156 square miles, pressed toward homes, cabins and other buildings in mountainous Pine and Featherville, about 70 miles east of Boise, fire officials said.
By Wednesday, more than 600 firefighters from 28 states were on the scene, KTVB reported.
The relentless fire was only 5 percent contained, officials said.
The fire, sparked by a series of electrical storms late last week, destroyed at least 71 structures, KTVB-TV, Boise, reported. More than a dozen of the structures were homes, fire officials said.
Firefighters using water-dropping helicopters and planes alongside bulldozers, engines and other equipment focused on protecting threatened structures and burning out dry, flammable vegetation to curb the fire's advance, Elk Fire spokeswoman Madonna Lengerich said.
Similar burnout efforts were under way at the larger but more-contained Pony Complex fire, near the town of Prairie, slightly closer to Boise, whose flames charred more than 145,000 acres, or about 225 square miles of sagebrush and grass, authorities said.
Some residents were allowed to return home in Prairie Tuesday, officials said.
Officials had issued evacuation orders for Pine, Featherville and Prairie, but some residents chose to stay behind, KTVB said.
Gov. Butch Otter declared a state of disaster for Idaho Monday.