The Aspen Acres fire, now just shy of 100,000 acres, is expected to become more active Tuesday as hotter weather and stronger winds test firefighters’ efforts to protect communities on the fire’s western edge.

The fire, burning 99,077 acres across Pueblo and Custer counties, is 36% contained, as of Tuesday morning. It would be the seventh wildfire in Colorado history to top 100,000 acres; the last was the Lee fire in 2025 that burned 137,758 acres north of Rifle.

Fire officials said activity is expected to increase Tuesday afternoon on the fire’s western flank as temperatures and winds rise.

Near North Muddy Creek, about 2 miles northwest of Rye, firefighters are aggressively building defensive lines between the fire and nearby communities. Crews are also working to protect properties in the Rye area and communities farther north and west, including San Isabel.

Near Mingus Ranch in Wetmore, firefighters conducted controlled burns overnight to remove vegetation between containment lines and the wildfire.

“This is a critical piece of work toward achieving containment in that area,” officials with Alaska Complex Incident Management Team 1 wrote in a Tuesday morning update.

Fire activity also increased near Saint Charles Peak, where aerial crews helped limit growth and suppress hot spots. Night-shift firefighters reported no heat in spot fires there Tuesday morning.

Air operations are expected to continue Tuesday if weather conditions allow.

While fire activity remains low on the fire’s northeastern edge, officials said the area continues to be “a lurking threat.” Pockets of smoldering heat could threaten structures if highly flammable juniper trees ignite near populated areas.

Gold Mountain fire

The fire burning near Ouray is estimated at 36,965 acres and 12% contained, according to the Rocky Mountain Complex Incident Management Team 2, which took control of the fire Tuesday morning.

Firefighters are continuing work along the U.S. 550 corridor, just north of Ridgway and north to an area near Cow Creek.

When constructing firelines, they are connecting old roadbeds, meadows, rock outcrops and other natural features that provide a break in fuels. The fire spread into the West Fork of the Cimarron and spotted over the Middle Fork and into the East Fork of the Cimarron. Crews are working to stop the fire from spreading farther north, fire officials said.

Lower temperatures and higher relative humidity levels are expected over the fire as moisture increases, officials said. Thunderstorms are likely this afternoon, which can bring lightning and erratic winds with up to 45 mph gusts.

Ferris fire

Favorable conditions helped crews increase containment on the western and southeastern sides of the fire, said Nick Cleary, operations section chief with California Interagency Incident Management Team 7, in a Tuesday video briefing.

The 64,869-acre fire is 29% contained.

About a quarter inch of rain fell on the eastern side of the fire, which helped calm fire activity, Cleary said.

“Good for fire behavior, good for fire activity. Bad for the resources out there trying to get back to a safe area and not get stuck on the line,” he said.

More heavy equipment is coming to the southeastern side of the fire to repair damages and minimize soil erosion and environmental impacts caused by firefighting.

Willow fire

More than 1,000 homes are still at risk as the Willow fire, a few miles from Leadville, burns 6,408 acres, the California Interagency Incident Management Team 8 said Tuesday morning. The team took command of the fire Tuesday morning.

The fire, which officials believe was caused by a person, is 29% contained. Details as to why investigators believe the blaze was human-cause were not immediately known.

Crews Tuesday are working to strengthen containment lines south of Turquoise Lake and begin establishing containment near Bald Eagle Mountain, west of Leadville, officials said

Aerial crews will continue Tuesday to drop buckets of water to cool down the edges of the fire where needed.

Erratic winds continue to challenge firefighters battling the Willow fire, said Jason Flores, operations section chief with the California team.

“It’s almost constantly changing on a daily basis, on an hourly basis,” Flores said.

Elk fire

The Elk fire burning in the Uncompahgre Wilderness north of Lake City grew slightly and is now estimated at 546 acres, Hinsdale County officials said Tuesday afternoon.

More than 200 personnel are assigned to the fire, as it remains 0% contained.

The fire became more active Monday as fire spread through heavy dead and downed timber — between 70% and 90% of the fuels in the fire area are dead trees, officials said.

Flames are burning in extremely remote and rugged terrain that is difficult for firefighters on the ground to access. If there was a medical emergency or if the fire were to shift direction, it could be challenging to get firefighters to safety. So instead, firefighters are using indirect tactics around the perimeter of the fire, using natural barriers, roads and other landscape features to build firelines and protect values at risk.

People living in parts of Hinsdale County and Gunnison County have been warned to be ready to evacuate if the fire grows or shifts direction.

Thunderstorms are expected Tuesday afternoon and evening. Officials expect winds up to 50 mph and an increase in moisture.

This is a developing story that will be updated.