In the face of the growing Sheep Fire, evacuation orders went out Thursday afternoon for the Essex area on the southern edge of Glacier National Park.

The Flathead County Sheriff’s Office issued a “mandatory and immediate” evacuation order after the 1,111-acre blaze reached a trigger point about three quarters of a mile south of Essex when it started spreading down a ridge toward McDonald Creek.

Later Thursday, U.S. 2 closed to traffic between mile markers 176.5 and 185, along with the BNSF rail line. The highway section also had been closed for two days last week, but reopened to traffic guided by pilot cars as the fire burned about a half-mile away.

Essex had been under a pre-evacuation warning since Aug. 19, and undersheriff Dave Leib said Thursday afternoon that the evacuations began around 2:30 p.m.

People who live in the area will not be allowed to re-enter the closed portion, which stretches from the Goat Lick Bridge on U.S. 2 west to the Schellinger gravel pit.

Essex is home to a population of 59, according to the U.S. Census. Leib estimated about 70 people would be affected by the evacuation order.

Gregg Dinetto, a spokesman for the incident management team fighting the fire, said increased fire activity prompted the evacuation, but no structures were imminently threatened.

“The evacuation, although mandatory, is somewhat precautionary to allow people to evacuate in an orderly fashion and to allow our folks to get themselves established,” Dinetto said.

While the wind hadn’t picked up significantly by mid-afternoon Thursday, the inversion over the fire had lifted, resulting in higher fire activity.

“It was putting up some pretty nice columns and you’re seeing lots of flame,” Dinetto said. “From what I saw at this time, it’s still basically about the same distance [from Essex], but it’s still up there on the ridge a ways and has a decent potential for making a run, especially if there were some winds behind it.”

Firefighters were prioritizing structure protection in Essex while helicopters drop retardant and water on the fire front.

A structure protection task force of five fire engines and 15 personnel from the West Valley, Martin City, Whitefish, Bigfork and Creston fire departments was dispatched to the Essex area around 2 p.m. Thursday.

Office of Emergency Services planner Nikki Stephan said they will be working with the incident management team’s structure protection group in Essex.

Dinetto noted that no aerial surveys had been conducted on the blaze as of Thursday evening, but that the fire’s behavior overnight would determine what actions the team takes. Helicopters continued to drop buckets of retardant and water on the fire front while hand crews thinned vegetation closer to Essex.

“The biggest effort has been the fuel breaks that they have been working on from Essex south to McDonald Creek,” he said. “It’s a 50- to 100-feet wide, following the railroad corridor. They’re removing understory and thinning trees out.”

If the crews can finish the fuel break prior to an advance by the fire, Dinetto said it will allow firefighters to conduct backburns to eliminate fuels in front of the blaze, as well as making it easier to run water pumps and hoses for direct attack on the ground.

While the distance of the flame front from the highway and BNSF line was holding at about a half mile and a quarter of a mile, respectively, that side of the fire was also showing higher activity Thursday.

“Some of the perimeter of the fire above the river area was also becoming more active, and was basically starting to organize itself,” he said. “Some of these little fires that might have been scattered around are starting to come together, build up some heat and become much more active, having much more potential for spread and spotting.”

The forecast doesn’t favor the firefighters.

“The next few days are going to be critical from a fire weather standpoint,” Dinetto noted. “Certainly it’s got the potential, maybe not the probability, to continue heading down the ridge, and potentially north toward Essex.”

Humidity is expected to stay low the next few days, with steady heat and gusts up to 30 miles per hour today. An overnight inversion is forecast to break by the early afternoon.

On Saturday a fire weather watch is in effect for the area from noon to 10 p.m., as a cold front boosts wind speeds and the potential for isolated thunderstorms.

An evacuation center has been set up at West Glacier School by the American Red Cross.

Anyone evacuating to a Red Cross shelter should bring essential items for each member of the family (if possible), according to communications director Anna Fernandez-Gevaert:

q Prescriptions and emergency medications.

q Foods that meet unusual dietary requirements.

q Important personal documents.

q Extra clothing, pillows, blankets, hygiene supplies and other comfort items.

q Supplies needed for children and infants, such as diapers, formula and toys.

q Special items for family members who are elderly or disabled.

The Red Cross will try to provide what people cannot bring with them, Fernandez-Gevaert said.

The fire information hotline for the Thompson-Divide Complex is 406-387-4854.

Reporter Samuel Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.