CHEYENNE, Wyo. (AP) — Strong winds fanned two Rocky Mountain wildfires Wednesday, prompting new evacuation orders as one spread toward communities outside Rocky Mountain National Park.

Cool autumn weather had been helping firefighters in their efforts to quell the Mullen Fire in southeastern Wyoming and northern Colorado, and the Cameron Peak Fire in northern Colorado. But gusts of 70 mph (110 kilometers per hour) have complicated their efforts.

Forecasters expected dry air and strong wind to pose a challenge for firefighters into the weekend.

The fierce burning is occurring much later in the year than usual. Mountain snows usually are significant enough to end fire season well before mid-October.

The latest evacuations in the path of the Cameron Peak Fire affected mainly recreational properties — including hundreds of mountain cabins — in and around the communities of Glen Haven and Drake east of Rocky Mountain National Park.

The fire continued spreading into remote northern Rocky Mountain National Park and was bearing down on the Colorado State University Mountain Campus a few miles (5 kilometers) north of the park.

“We’re preparing to do whatever is necessary in those areas,” fire operations trainee Tim Daly said in a briefing about the efforts to protect the campus and communities.

The main route to the park from the east, U.S. Highway 34, remained open but under a voluntary evacuation notice, meaning people who need extra time to leave their homes along the highway should consider doing so.

Mandatory evacuation zones for the first time extended to the foothills just west of Fort Collins, Colorado. The city of 168,000 people on the edge of the plains wasn’t considered at risk but residents awoke Wednesday to thick smoke and poor air quality alerts.

Fort Collins schools kept children indoors at recess and told parents that switching entirely to online teaching was an option if the smoke continued. Students already were being taught online part of the week due to the coronavirus pandemic.

At more than 210 square miles (540 square kilometers), the Cameron Peak Fire was less than 10 square miles (16 square kilometers) from becoming the biggest in Colorado history. Firefighters fully contained the state’s biggest in history, the Pine Gulch Fire north of Grand Junction, on Sept. 15.

The Cameron Peak Fire has damaged or destroyed 95 buildings, including 33 homes, while the Mullen Fire 25 miles (40 kilometers) to the north in Medicine Bow National Forest has destroyed or damaged 65 structures. Both fires affected primarily recreational subdivisions and isolated cabins, not cities or towns.

Firefighters planned to focus on holding their ground against the 275-square mile (700-square-kilometer) Mullen Fire, which was 34% contained, despite the gusty winds, fire operations section chief John Wallace said in a live-streamed public briefing Wednesday.

“There’s a lot of blowing debris out there, a lot of ash blowing around. So the conditions are really nasty for us,” Wallace said.

Crews were preparing to study how to reseed trees and prevent future erosion from happening in the burned areas, some of which were beginning to reopen to homeowners.