A fire near Silverthorne had crews scrambling to contain it to the forest, away from neighborhoods, with ground crews unable to safely attack it as of Monday night.

The Ptarmigan fire — located on Ptarmigan Mountain near Silverthorne, primarily on federal land in the White River National Forest — was reported around 4:30 p.m. Monday, officials with the U.S. Forest Service and Summit Fire and EMS said in Monday evening news releases.

Not long after, the Summit County Sheriff's Office ordered evacuations for about 200 residents in the nearby Hamilton Creek neighborhood, and pre-evacuations were put in place for the Angler Mountain and South 40 neighborhoods, officials said.

No homes were immediately threatened by the fire, a spokesperson for Summit County said Monday evening. At the time, the fire totaled 30-40 acres, according to a Forest Service estimate.

Firefighters hadn't been able to safely battle the blaze on the ground as of press time Monday evening, but were "staged in strategic places, should they have the opportunity," U.S. Forest Service officials said.

The fire was fought Monday by a heavy air tanker, two single engine air tankers and a heavy helicopter, all guided by an air attack plane. Efforts were focused on "keeping the fire from moving downhill toward structures," the Forest Service said.

A joint command of Summit Fire & EMS, Summit County Sheriff's Office and U.S. Forest Service officials took initial management of the blaze. Additional air resources and firefighters from the Forest Service were expected to arrive on scene Tuesday morning, officials said.

Low temperatures and relatively high humidity were expected overnight, creating favorable firefighting conditions. Additionally, a cold front was expected to arrive Tuesday, Summit County officials said, which would further aid firefighting efforts.

Firefighters planned to remain in evacuated neighborhoods overnight Monday to monitor the fire.

“Our goal is to keep the fire away from developed areas and hit it hard in the morning," Summit Fire & EMS Chief Travis Davis said at a Monday night fire briefing, according to a Summit County spokesperson.

A Red Cross emergency shelter was opened Monday night at Summit Middle School, 158 School Road in Frisco, officials said, adding that both the middle school and Silverthorne Elementary School were expected to operate normally Tuesday.

The shelter will follow CDC guidelines regarding the COVID-19 pandemic, employing social-distancing protocols, health screening and masking, Red Cross officials said in a Monday evening press release.

Recreational access to Ptarmigan and Angler mountains has been closed, and the flying of drones is "strictly prohibited" around wildfires because of the potential to interfere with aerial firefighting, Summit County officials said.

Locals can call (970) 668-9700 for the latest information on the fire, they added.