A wildfire in the Bob Marshall Wilderness grew to 7,000 acres and burned closer to an area with about 65 summer homes as Montana's dryness and heat persisted Tuesday, and the state remained in forest-fire emergency status declared by the governor.

The declaration Monday by Gov. Brian Schweitzer increased authority for the state Department of Natural Resources and the Montana National Guard to spend money for aggressive initial attack on fires. Western Montana's fire risk is classified as "extreme," with fire managers finding unprecedented potential for new blazes and rapid growth of fires, said Nick Spang of the Lolo National Forest staff.

Growth in the Bob Marshall's Ahorn fire burning heavy timber some 30 miles west of Augusta put the blaze about two miles from the area of homes and some Forest Service buildings known as Benchmark, fire spokesman Jack de Golia said. Occupants of homes in the Benchmark area received "pre-evacuation notices," informing them that leaving on short notice may be necessary, de Golia said. Some of the summer homes were not occupied, he added.

Protecting structures was the focus for most of the 83 firefighters assigned to the blaze, started by lightning last Wednesday.

Also burning in the Bob Marshall Wilderness was the Fool Creek fire, measured at nearly 6,000 acres. Aerial water drops hit hot spots and a Forest Service cabin remained in protective wrapping as a fire defense.

Twelve new fires started Monday in southwestern Montana's Bitterroot National Forest after a thunderstorm, but none became major, forest spokeswoman Nan Christianson said. She praised the work of initial-attack crews, saying there were "running and gunning" to successfully corral fires before they spread significantly.

Christianson said resources were stretched and more firefighters were due to arrive Tuesday. Fire managers expected 40 from Alaska and eight from Arizona.

"All of that's going to help with the resources we have on the ground already," Christianson said.