A fire burning in the Medicine Bow National Forest roughly tripled in size Wednesday night into Thursday morning as firefighters work to protect buildings and establish containment lines.

The Keystone Fire grew to roughly 1,300 acres Wednesday night, said Rocky Mountain Team Blue Operations Section Chief Rob Powell in a video update Thursday morning. The blaze is located some 1.5 miles southwest of Rob Roy Reservoir, 1.5 miles northwest of Keystone and two miles south of Rambler.

As of 7 a.m. Wednesday, the fire had been estimated at 376 acres in size. Roughly 150 firefighters and incident management personnel were working the blaze at that time.

Powell said some 60 percent of the fire is burning in timber which has been killed by the mountain pine beetle, which has wreaked havoc in forests throughout the western U.S. and parts of Canada.

Beetle-killed trees dry out and become brittle, making it more dangerous for fire crews to fight the flames.

"It's just too dangerous to get into the fuel type, due to all the snags and the heavy dead and down [timber], and the active fire behavior that we're at with no escape routes and no safety zones," Powell said. "That's why we have to go bigger."

Like last year's Beaver Creek Fire near the Wyoming-Colorado border, the Keystone Fire is expected to be a "long-duration fire," Powell added.

Buildings in the Keystone area are the focus of structure-protection efforts currently underway. Sprinkler systems and other means are in place to prevent the fire from damaging any buildings, which Powell says is the main focus of fire managers at this point.

On the northern edge of the fire perimeter, crews are working to prevent the fire from moving into a wilderness area.

Authorities emphasize that people should stay out of the area west of Albany, which includes Rob Roy and Keystone. All dispersed campers in the area were asked to relocate, and U.S. Forest Service officials hoped to have an area closure in place by Wednesday evening.

The communities of Keystone, Rambler and Lake Creek, as well as Rob Roy Campground, were evacuated.

Carbon Power and Light has cut power to the area. There is not currently an expected time when evacuees will be allowed to return.

An evacuation center was established Monday at Harmony School on Highway 230, but has since been put on standby and is not presently open. Anyone who needs help as a result of the fire can call the Red Cross at 307-222-8272.

Displaced animals can be sheltered at the Albany County Fairgrounds in Laramie.

A community meeting regarding the blaze will be held at 7 p.m. Thursday at the Centennial School in Centennial.