The expanding size of the Ahorn wildfire, coupled with the extreme high temperatures and severe drought conditions, prompted Lewis and Clark County officials to declare a local fire emergency situation Tuesday afternoon.

The blaze, burning about 20 miles west of Augusta in the Lewis and Clark National Forest -- and Lewis and Clark County -- jumped from about 4,000 acres Monday afternoon to more than 7,000 acres and is now threatening 65 homes.

The Lewis and Clark County Sheriff's Office is issuing pre-evacuation warnings, which have a checklist for items to remove and safety precautions for occupants of the mostly summer homes, as well as contact numbers in the Benchmark area about two miles from the fire.

Tuesday afternoon, the flames were moving north, fire spokesperson Jack De Golia said.

A contracted helicopter dumping water was expected to continue dousing the flames during the night, he said. On the ground, firefighters focused on protecting structures with fire-retardant wrapping and foam in addition to sprinklers.

"It's too dangerous to put people on it right now," he said.

The Ahorn fire is thought to have been sparked by lightning on June 28, but first seen on July 11.

The Forest Service is considering closing large areas of land especially in the Lewis and Clark National Forest, he said.

Another fire in Lewis and Clark County in Wolf Creek is still being worked on by firefighters but has not grown from Monday night, when it charred 50 acres near Lyons Creek Road, Wolf Creek Volunteer Fire Chief Rocky Infanger said. The handful of residents advised to evacuate the area returned home while helicopters continued to dump buckets on the blaze, he said.

"It's looking good up there," Infanger said.

Stage one fire restrictions also were put into place as of Tuesday afternoon in Lewis and Clark County.

"Record-breaking heat, dry conditions and the threat of thunderstorms have created the need for extreme caution in avoiding new fires," Lewis and Clark County Commissioner Ed Tinsley said.

Under the regulations, campfires may be built only in developed recreation sites. Campfires in rock rings and the use of wood stoves in canvas tents outside of the campgrounds and other developed sites are prohibited.

Restrictions on smoking and open fires on federal and state lands, as well as private forested lands in the county are now in effect.

Smoking in the affected areas is prohibited outside of buildings, vehicles and developed recreation sites.

These restrictions do not apply within Helena city limits or to activities that land-managing agencies have specifically permitted. Officials who manage state and federal lands in Lewis and Clark County have said similar restrictions will take effect on Friday.