Another 100 firefighters were expected on Friday to join crews battling a forest fire that continued to burn out of control above Alpine overnight and was again threatening some homes.

Uinta National Forest officials said Friday morning that crews have no idea when the blaze, which has blackened about 275 acres, will be under control. Friday's reinforcements swelled firefighter numbers to about 250.The number of firefighters battling the Alpine blaze rose from 83 to about 150 Thursday, including an Indian crew from New Mexico and an elite overhead management team from Oregon that will direct firefighting efforts.

Firefighters from Duchesne, the Park Service and Dixie National Forest also were battling the blaze.

Crews also got a boost from several air drops of fire retardant. Nevertheless, the fire jumped firebreaks and continued spreading.

Danger to homes subsided somewhat Thursday after winds whipped the fire up Fort Canyon away from isolated residential areas. But by Friday morning, the blaze had jumped the canyon and was heading back toward homes located northwest of Alpine Park.

"It completely jumped the line," Loyal Clark, Uinta National Forest information officer, said Thursday afternoon. "We lost everything we put in the night before. So now we start over."

Officials believe the blaze was sparked Wednesday afternoon by an abandoned campfire above Sliding Rock in Fort Canyon. After jumping firebreaks northeast of the blaze on Thursday, the fire headed north toward heavy timber in the Lone Peak Wilderness area.

"What we are concerned about here is that this is part of the watershed for Alpine," Clark said. She said the area, stripped of vegetation, could be ripe for flooding similar to that experienced by areas above Lindon and Orem a year ago this month.

A couple weeks after an August

ire destroyed mountainside vegetation above the two cities, heavy rains sent water gushing down the mountain and into nearby subdivisions.

"The Wasatch Front is so valuable for watershed that you really can't put a dollar value on it," said Roy Daniels, Uinta incident commander. "Our main plan of attack is to minimize acreage (burned). We hope to hold it to less than 300 acres."

Meanwhile, a fire near Powder Mountain ski resort that was contained Sunday raged out of control Friday morning, as strong winds activated hot spots along the blaze. The resurgence has increased the total number of burned acres to 2,000, according to Kathy Jo Pollock, Interagency Fire Center spokeswoman.

A third fire erupted Thursday in Wallsburg, near Deer Creek Reservoir. The fire claimed more than 400 acres by Friday morning, an Interagency Fire Center dispatcher said.

Tom Tidwell, Spanish Fork district ranger, issued a renewed call for people to honor a special fire closure that went into effect Tuesday in Utah, Wasatch and Juab counties. The closure prohibits open fires of any kind, except campfires in facilities such as improved recreation sites on state, county and national forest lands.

In addition, the fire closure prohibits burning of any kind within 500 feet of any mountainous or brush-covered area.