Firefighters struggling to tame a 2,300-acre wildfire that closed Yellowstone Park's east entrance faced the prospect of even more dry weather and erratic wind.

Fire information officer Sarah Gracey said the wind could push embers up to a half-mile east of the fire, which was being fought by more than 800 firefighters and 11 water-dropping helicopters late Thursday.

"This fire really has the potential to become quite large," she said.

Employee housing inside the park and the historic Pahaska Tepee resort just outside the gate remained threatened by the fire, she said.

"What makes this fire so difficult is the inaccessibility, the steep terrain, the winds and the wind patterns," fire information officer Bobby Kitchens said.

Wind has hindered the use of tanker planes on the blaze, Kitchens said. Two more water-dropping helicopters were expected to arrive Friday.

Pahaska Tepee resort owner-manager Angela Coe estimated that about 220 people visited on Thursday, with about six guests staying overnight. It was welcome relief for her after a flurry of cancellations during one of the busiest times of the year.

"It's going to hurt for long after the fires are out," she said.

She estimated that the resort, which features a hunting lodge built in 1904 by Buffalo Bill Cody, was losing about $10,000 a day in business, although that is offset by about $2,000 from serving fire crews.

Last year, more than 333,000 visitors passed through the park's east entrance.

Some firefighters headed to a dozen or so lodges east of the park to set up sprinklers and clear brush around the buildings in case the fire grew, Fire spokesman Bob Summerfield said.

The park as a whole and its four other entrances remained open.

Firefighters southwest of Jackson finally succeeded Thursday in completely containing a blaze that charred 4,470 acres and, at its peak, had threatened more than 100 homes.

In the Black Hills, firefighters worked Thursday to contain two lightning-sparked blazes that have burned 16,000 acres along the South Dakota-Wyoming border.

Other fires were burning in Montana, Colorado, Idaho, California, Nevada and South Dakota.