Hail and rain fell around the Mount Graham International Observatory, aiding the battle to tame the fires. But lightning from a thunderstorm sparked a new fire Saturday afternoon in the steep terrain on the mountain's southside.
Fire officials also worried about possible flooding in the canyons because the burned soil would not be able to absorb the rain.
``It can be positive and it can be harmful, depending on where it falls and how fast it falls,'' Beth Wilson, a spokeswoman for the team fighting the fire, said of the rain.
By Saturday night, the Nuttall and Gibson fires were 55 percent contained. They have charred 28,000 acres on Mount Graham since lightning sparked them in late June.
So far, crews have been able to protect the observatory and the mountain communities of Turkey Flat and Columbine. Bulldozers cleared out the vegetation in a 200-foot ring around the observatory, home to some of the world's most advanced telescopes.
``You never want to say that you are 100 percent sure that everything is safe, but we are feeling real good,'' said Paul Summerfelt, deputy incident commander for the firefighting team.
Fire managers, however, said they didn't know when residents evacuated from Turkey Flat's 74 cabins and Columbine's 15 cabins would be able to return home.
The fire's unpredictable nature has tested the nerves of Judy Rhoads, whose Turkey Flat cabin has been in the family for 60 years.
``I thought 'You can breath easier' was a cliche, but it really is true. I must have been taking a lot of short breaths this week,'' Rhoads said.
About 800 firefighters were fighting the wildfire Saturday, but officials planned to reduce the number to 200 by Tuesday.
The fire damaged the steps of a lookout tower and destroyed a building containing communication equipment.
