Lightning started a half-dozen new wildfires early Tuesday, adding to blazes that already had charred more than 50,000 acres of northern Nevada.

More than two dozen fires were active, many out of control, scattered from the heavily timbered western front of the Sierra Nevada near Reno to the sage- and grass-covered rangeland 300 miles east.

As many as 300 homes and businesses east of the capital, Carson City — including a legal brothel — were threatened by a pair of brush fires that expanded overnight to 6,000 acres.

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"We're actually waiting at the door to leave," said Bunny Love, an employee at the Moonlite Bunny Ranch. "The girls all have their bags packed."

In Arizona, a 49,700-acre wildfire north of Grand Canyon National Park had jumped the only highway leading to the remote North Rim, closing the road and marooning hundreds of tourists and workers. The fire was burning about 30 miles from the park, and officials said no one was in any danger.

"The canyon is covered in smoke," Amber Boeldt said in a telephone interview from the Grand Canyon Lodge, where she and her family were staying on the North Rim. "That's all you can smell."

On Monday, an estimated 200 of the 950 stranded people drove for two hours on a forest road around the fire to Fredonia, near the Utah state line, said park spokeswoman Maureen Oltrogge. The remainder were to be escorted out Tuesday.

Nevada's biggest fire had grown to 40,000 acres in Carlin, where the University of Nevada Fire Science Academy is located.

"We do a lot of real-life fire training, but we never expected this," said Denise Baclawski, the academy's executive director. "All night long we had staff members work to protect the facility."

Northwest of Reno, a 1,500 acre wildfire in the Sierra just across the Nevada-California line was estimated to be 50 percent contained early Tuesday.

Near Sedona, Arizona, fire officials predicted that the 4,200-acre fire that forced hundreds to evacuate Oak Creek Canyon would be contained Wednesday. Owners of the roughly 400 homes and scattered businesses still evacuated were expected be allowed to return Tuesday night.

Elsewhere, a 3,200-acre blaze a mile west of the northern New Mexico town of Gallina calmed and evacuees from 120 homes in three subdivisions were allowed to return Monday.

As of Monday, wildfires around the United States had blackened 3.3 million acres this year, compared with 1.2 million acres on average at this point in the fire season, the National Interagency Fire Center reported. However, much of this year's acreage resulted from huge grass fires in Texas and Oklahoma this spring, not from forest fires.