SALT LAKE CITY -- Firefighters were working on Monday to contain several lightning-caused blazes in the state, including one in Skull Valley that was threatening more than 20 structures.
The 4.5 square-mile Patch Springs Fire grew overnight as it approached the nearby Goshute Indian Reservation.
Firefighters were trying to secure the southern edge of the blaze, several miles from the town of Terra and homes on the reservation, fire information officer Joanna Wilson said.
Twelve homes, five commercial properties and five outbuildings such as sheds and barns were threatened, but no evacuations had been ordered.
Officials expected hot and dry conditions to continue, with wind gusts from the southwest.
Wilson said sandy roads in the area have made it difficult for crews to move their vehicles.
Roads and hiking trails were closed, and officials ordered three additional engines and another helicopter to assist the effort.
In northern Utah and across the border into Idaho, crews were battling a blaze that has charred more than 25 square miles. The State Fire near Portage, Utah, was 42 percent contained.
It was less than a mile from the Idaho town of Samaria.
A hotshot crew constructed a fire line on the town's southern edge, so the threat to homes was minimal, fire spokeswoman Jennifer Hansen said.
Two Utah National Guard Black Hawk helicopters were assisting the effort from the air.
Gov. Gary Herbert has authorized National Guard members to help fight the wildfires burning in the northern part of the state.
The governor's office said in a statement that extra air support from the Guard gad been requested to help battle flames in steep canyons. Fires in other parts of the state have diverted scarce air resources, it said.
Hansen said a national incident command team was expected to take over management of the fire on Tuesday.
A third helicopter was deployed against the Millville Fire in Cache County, which has burned more than three square miles. About 150 firefighters were working to build a fire line around the blaze. No structures were threatened.
A red flag warning had been issued for the area, with the possibility of gusty winds and dry lightning until Monday night, U.S. Forest Service spokeswoman Charity Parks said.
Fire officials were also monitoring the 6-acre Mount Elmer Fire, which broke out Friday in the Mount Naomi Wilderness. Crews were not staffing the fire because resources were deployed against higher-priority blazes.