The Emigration Canyon fire grew by only 200 acres overnight, thanks to a mellowed-out Mother Nature.

But fire officials remained cautious about saying whether homes in the upper canyons remain threatened.Crews on Sunday repelled the fire's taunts at homes in Pinecrest and Killyon canyons, according to Ray Tate, spokesman of the Interagency Fire Center, who declined to say if the structures were out of harm's way.

"We won't say those homes are out of danger until the fire is completely out. But most of the (fire's) growth overnight was away from the homes."

Fresh crews arrived Sunday and on Monday morning pounced on the three-day, 5,400-acre fire. Tate said firefighters from as far away as Alaska and Maine have joined the battle, bringing the Emigration fire force to 300.

Tate said about 1,000 acres burned on Sunday, but only about 200 were scorched during the night. The fire has moved into the Freeze Creek area and penetrated slightly into Red Butte Canyon. "Fire lines along the western and eastern flanks have pretty well been established," said Tate. But the blaze is still quite active on the southwest section, about a quarter of a mile north of the Emigration Canyon road.

There have been no injuries on the fire lines, although a firefighter Sunday night suffered an asthma attack, aggravated by the smoke, Tate said. He was treated at University Hospital, then released. "He's OK now."

Although weather was favorable Sunday, a weak storm front expected to brush across northern Utah Tuesday may bring good news and bad news for firefighting efforts, said Paul Duval, lead forecaster for the National Weather Service.

The front could bring cooler air but will also likely carry steady winds that could gust, making firefighting a tricky enterprise.

Duval said, however, that winds will be changing from easterly to westerly, which will bring relief to Salt Lake residents, who have been breathing the smoke from the Emigration fire.