Nature has helped firefighters control a Hobble Creek Canyon blaze that charred 150 acres of grass and oak brush since Tuesday afternoon.

"Autumn's colder nights, lower day temperatures and dew reduce the time the fire can burn," Loyal Clark, Uinta National Forest spokeswoman, said. "This would have been a much worse fire if it happened this summer."Larry Call, Uinta National Forest planner, said crews expected to have the fire contained late Thursday morning, and extinguished by Saturday.

"They will have a ring around it, then they can move in to deal with one spot at a time," he said.

One hundred firefighters from Utah and surrounding states have fought the fire. Officials at the Sawtooth National Forest in Idaho sent a helicopter, which was used to drop water on oak brush to keep it from burning.

The fire began just west of the Hobble Creek Golf Course. It burned away from nearby Kelly's Grove, a subdivision with about 22 houses. The fire also stopped without crossing Pole Haven Road. If it had, it would have been fueled by deep timber rather than oak brush, and the blaze would have been much harder to put out, Call said.

Officials believe the fire was started by sparks from a damaged power line.