The Kruger Rock fire near Estes Park is now 60% contained and did not grow after spreading only one acre overnight, according to the U.S. Forest Service.

The wildfire had burned 146 acres as of Thursday evening, the agency said. The fire sparked Tuesday morning, quickly burning nearly 140 acres in its first 24 hours.

More than 200 firefighters were working to contain the blaze Thursday morning.

Cooler temperatures, lighter winds and overnight precipitation helped crews battle the blaze on Wednesday; however, the weather could take a turn for the worse in the coming days.

NEWS | Kruger fire in Estes Park

A Red Flag Warning is in effect in Larimer County until 5 a.m. Friday as warm temperatures, low humidities and strong winds are expected to produce an increased risk of fire danger, according to the National Weather Service.

West winds were predicted to reach 40 mph by Thursday evening, the National Weather Service said.

Mandatory evacuations are in place for Hermit Park and Pole Hill Road to the Panorama Peak area on the east side of U.S. Highway 36, according to the Larimer County Sheriff’s Office.

On Wednesday, fire officials downgraded evacuations from mandatory to voluntary for the area south and east of Fish Creek Road and Little Valley Drive. Those in voluntary evacuation areas should be prepared for mandatory evacuations if the fire behavior changes.

The sheriff’s office said the blaze began after high winds knocked over a tree, which fell into a nearby power line. That created an arc, which ignited the fire.