The 14,250-acre blaze had gotten to within about a third of a mile of homes around Whiteriver, headquarters of the White Mountain Apache Tribe.
Elsewhere in the Southwest, Mesa Verde National Park in Colorado was closed to visitors for the second time in two years because of wildfires and authorities said Wednesday the flames threatened the park's historic ruins.
As many as 5,000 people had fled their homes in Whiteriver and other communities on the Fort Apache Indian Reservation.
Carrie Templin, a spokeswoman for the firefighters, said there was a potential for wind that could drive the Kinishba fire and thunderstorms that could produce lightning but little rain in the forested mountains of eastern Arizona.
``If we have lightning, we'll definitely have (new) fires,'' Templin said. Lightning started at least three new fires in the area Tuesday but they were quickly neutralized.
The fire was started by lightning Sunday east of the starting point for last summer's Rodeo-Chediski fire, the largest wildfire in state history. Last year's fire charred 469,000 acres and destroyed 491 homes.
The latest blaze had gotten to within four miles of a point that would trigger evacuations in Pinetop-Lakeside and mountain communities about 20 miles to the north, where the population swells to 30,000 in the summer.
Lightning started at least six fires Tuesday in Mesa Verde, in the southwest corner of Colorado, and Assistant Superintendent Betty Janes said all visitors and the park's 30 to 50 residential employees were evacuated.
Five of the fires were still burning Wednesday inside and outside the park. The total acreage burned was estimated at 200 acres, said Larry Helmerick, fire information officer for the Rocky Mountain Area Coordination Center.
Helmerick said the stone ruins were considered threatened, but didn't immediately have details on how they would be affected.
In 2000, two wildfires charred more than a third of the park's 52,000 acres, and a blaze in 2002 blackened more than 2,600 acres. The park holds some 25,000 archaeological sites left by an Indian culture that vanished more than 700 years ago. Its cliff dwellings date to the 1200s and pit houses date to the 500s.
In Wyoming, the Snake River was reopened to recreational use Wednesday after being closed for three days because of fire. July is the peak business month for rafting operations and fishing outfitters, with as many as 8,000 people a day floating down the river.
``I know they hit the river as fast as they could this morning,'' said Jay Kriss, Bridger-Teton National Forest spokesman.
The 3,200-acre fire was 20 percent contained, Kriss said.
Fires also were active in Idaho, Montana, New Mexico, Nevada, Utah, Oregon and Washington, the National Interagency Fire Center said.
