Pre-evacuation orders for the Ptarmigan Fire burning near Silverthorne were lifted Monday afternoon as firefighters achieved 55% containment, the U.S. Forest Service announced.

This comes as the fire has burned approximately 86 acres since it was reported one week ago on Sept. 27. The cause of the fire is still unknown, fire officials said.

The fire prompted evacuations and warnings for more than 600 residents in surrounding neighborhoods on Monday and Tuesday. Those orders were downgraded to pre-evacuation Thursday.

The pre-evacuation status has now ended for the Hamilton Creek, Angler Mountain Ranch, South Forty and Ptarmigan neighborhoods.

Firefighters reach 20% containment on Ptarmigan fire

Members of the public are still asked to avoid the forest closure area, including Angler Mountain and Ptarmigan Peak Trails.

Around 150 firefighters were working the fire Monday evening, down from nearly 300 firefighters on Friday, according to the U.S. Forest Service.

“Efforts will continue through this week and beyond to fully contain and ultimately extinguish this fire, which is burning in heavy forest littered with dead-standing and downed timber,” the Summit County Fire Department said in a statement.

Though there is no estimated date, the Summit County Sheriff’s Office said it plans to hold a community meeting after the fire has reached 100% containment.