FORT COLLINS — As the Cameron Peak fire forced more mandatory evacuations Friday, firefighters have focused on the southeastern end of a wildfire that’s burned for nearly two months and now threatens to roll through Colorado State University’s Mountain Campus.

The fire was “extremely active” throughout the day Friday, officials said, and firefighters had expected it to reach the mountain campus, roughly 25 miles north of Fort Collins, earlier in the day. By dusk, the campus was “under siege,” fire operation trainee John Norton-Jensen told firefighters at a briefing in Loveland. Norton-Jensen said resources were stretched and the fire couldn’t be put out with what’s available, so containment efforts would be prioritized around the campus and the hundreds of structures in its area.

“The mission is you guys are going tonight,” Norton-Jensen told the assembled crews, adding that the fire was “pretty damn close” to campus and that the overall spread –131,231 acres torched as of Friday — was “taxing” first responders. “It’s going to be a long night.”

At a Friday evening press conference, Norton-Jensen said the fire was on both sides of the campus and that firefighters there were preemptively burning areas in front of buildings.

The Cameron Peak fire has been burning since Aug. 13, when it started west of Fort Collins near Red Feather Lakes. As of Friday, it’s 44 percent contained. A Park Service ranger said Friday evening that while authorities are still investigating what started the fire, it’s believe the Cameron Peak fire was started by humans. A spokesman for the Larimer County Sheriff’s Office said that as of late September, more than 90 structures have been destroyed or damaged.

On Friday, the continued spread of the wildfire prompted more mandatory evacuations, affecting as many as 5,000 people, in the area south of Highway 14 and for residents from Larimer County Road 44H to County Road 27.

Larimer County Sheriff Justin Smith said at the press conference that “we’re potentially very close” to allowing people back into the Crystal Lake and Red Feather areas.

Colorado Highway 14 remains closed near the Kelly Flats campground, about 40 miles west of Fort Collins. Smoke hung over the mountains near town, blurring their features, and homemade signs thanking firefighters dotted the highway through the Poudre Canyon. One firehouse along the highway warned that fire risk was “very high.”

Burns flared up Friday near the Comanche Reservoir, driven by six days of low humidity, which means makes for drier vegetation for the fire to burn through, said Cass Cairns, a spokeswoman for the Cameron Peak response. Norton-Jensen said firefighters had success fighting the fire on the northern part of the fire and were “very close to containment” in some areas there.

Jered Kramer, the sheriff’s office spokesman, said he didn’t know how many people affected by Friday’s order had actually evacuated. Other residents in the area had previously been directed to evacuate; at one hotel in Loveland, where displaced residents were served chicken parmesan Friday evening, some people had been evacuated twice in October alone.

Expected weekend weather conditions for this weekend won’t help: The recent trend of low humidity will continue, officials said, which will mean more dry conditions. Winds expected to blow in with a cold front Sunday will further exacerbate the situation and will dictate in which direction the fire burns.

Temperatures are projected to drop below freezing on Monday and Tuesday mornings, said Aviva Braun, a meteorologist with the National Weather Service. The cold front is not expected to bring much moisture, however.

Seth Webb, the director of the Mountain Campus, said the school had been engaged in efforts previously to fortify the area against fires. Trees had previously been cleared, and crews have been working in the area since the beginning of the fire two months ago. Hoses, engines, equipment and other materials are already in place, waiting for the firefighters that Norton-Jensen briefed Friday night. Crews have also been — and will continue Friday night — preemptively burning areas near campus to “create some black” between the fire and the buildings, Cairns said.

“It’s not unexpected this day would arrive,” Webb said. “We’re holding out hope, though.”

The Mountain Campus has been cleared out since the fire began; Webb said only a skeleton crew of staff had been there to begin with. Firefighters who had been using it as a spike camp evacuated.

Webb said he hadn’t had time to consider the emotional impact of the fire ravaging campus, but he said that “seems inevitable” at this point.

“This is the most critical day in the two-month incident,” he added.