Hundreds of firefighters were cutting and digging containment lines Thursday around the growing Canal Fire, which has blackened more than 70,000 acres and damaged two homes in Millard County since June 25, when lightning sparked the blaze outside Oak City.

Burning about about 100 miles southwest of Salt Lake City, the blaze remained small for the first few days, but high winds Sunday whipped it into Utah’s largest fire of the season as it churned through the Canyon and Gilson ranges west of Leamington.

That town and the neighboring community of Fool Creek were evacuated Sunday, but residents soon were allowed to return. Flames have damaged a dozen minor buildings.

“Winds have picked up this afternoon [out of the west]. The eastern edge of the fire, especially the southeast, is the most active,” fire information officer Kathy Arnoldus said Thursday.

The fire was 20% contained as of Thursday morning.

Eighty miles to the north, meanwhile, fire crews hoped to fully contain the human-caused Knolls Fire that threatened Saratoga Springs over the weekend, forcing the evacuation of 13,000 residents (they were allowed to return Monday) and incinerating one home. Twelve others were damaged.

Knolls and Canal were the two most threatening of Utah’s many fires last weekend, both prompting relief through the Federal Emergency Management Agency.

The Knolls Fire was 97% contained Thursday, according to Utah Fire Info. Drier conditions and winds fanned some flare-ups within the 13,000-acre burn, which had ignited Sunday south of Saratoga Springs and west of Utah Lake, but those were quickly suppressed, according to Utah Fire Info.

A total of 162 personnel have been fighting the Knolls Fire, including eight engines, four 20-person crews and a helicopter.

While the response ramped down Thursday on the Knolls Fire, suppression efforts ramped up on the Canal Fire.

As part of an aggressive response, some 576 personnel, aided by an air tanker and five helicopters, were now on that fire. The fire has destroyed 12 “minor structures,” along with 20 other nonresidential structures, and damaged two homes, while burning some power lines, according to Arnoldus.

“We are focusing on stopping that southeast corner from advancing,” Arnoldus said. “The northern perimeter is looking good. We have some contained lines on that, moving on down the west side.”

Winds have been pushing the fire over the Canyon Mountains in the direction of Scipio, but flames remained miles away from that town on Interstate 15.

The U.S. Forest Service closed parts of Fishlake National Forest north of Oak City. The fire crossed State Road 132, but that highway remains open, while several back roads are closed to public use.

Correction: July 3, 8:55 p.m. • This story has been updated to report that the Canal Fire damaged two homes.