But authorities were still struggling at zero containment on the blaze, ranked as Arizona's second-largest forest fire on record. The so-called Wallow Fire has blackened 336,000 acres and cut through the popular mountain retreat of Greer.

The total number of firefighters battling the fire, believed to have been started by careless campers, was raised to over 3,000 on Thursday, from 2,000 the day before. Weather was expected to cooperate on Thursday with lower winds and temperatures and higher humidity, said Suzanne Flory, a U.S. Forest Service spokeswoman.

"There's still potential for growth, but the weather is going to be much more conducive to firefighting," she said.