DENVER — One of Colorado’s newest wildfires, the Derby fire, tripled in size overnight Tuesday and tripled again on Wednesday, torching more than 2,600 acres and destroying at least one building.

The Derby fire was mapped at 250 acres on Tuesday and roughly 850 acres on Wednesday evening. By Thursday morning, fire officials said the flames had burned 2,624 acres.

Five wildfires burning on Colorado’s Western Slope — the Lee, Elk, Derby, Stoner Mesa and Crosho fires — have together burned more than 165,000 acres, or about 258 square miles.

The fires have threatened hundreds of homes, evacuated Colorado communities and prompted state, U.S. Forest Service and Bureau of Land Management land closures across the western state.

The Lee fire burning in Rio Blanco County is Colorado’s fifth-largest wildfire on record. It’s only 5 acres away from becoming the fourth-largest, according to the state’s Division of Fire Prevention and Control.

Lee and Elk fires near Meeker

The Lee fire burning near Meeker in Rio Blanco County has seen minimal growth in the past few days as fire crews steadily increase containment.

At 137,755 acres, the Lee fire is the fifth-largest wildfire in Colorado on record, according to the state’s Division of Fire Prevention and Control. It’s also 5 acres away from surpassing the fourth-largest — the Hayman fire, which consumed 137,760 acres in 2002.

The Lee fire started seeing containment jumps Saturday, after rainy weather helped firefighters gain control of the nearby 14,518-acre Elk fire. As of Wednesday night, the Lee fire was 73% contained.

The two drought-fueled wildfires together destroyed five homes and 14 outbuildings.

Both wildfire burn areas are closed to the public, and multiple zones on the Lee fire’s southern edge remain under mandatory evacuation orders. Pre-evacuation orders remain active around the Lee fire, fire officials said.

The Colorow Mountain and Rio Blanco Lake state wildlife areas reopened on Wednesday, according to a news release from Colorado Parks and Wildlife. The Oak Ridge and Piceance state wildlife areas remain closed. The gates are open for fire crews’ access, but the public is asked to avoid the area.

Parts of White River National Forest and Bureau of Land Management property around the Lee and Elk fires also remain closed.

Derby fire in Eagle County

A quickly spreading wildfire that prompted mandatory evacuations in Eagle County on Tuesday tripled again in size on Wednesday.

The 2,624-acre Derby fire was discovered on “remote, rugged terrain” in the White River National Forest, about 15 miles from Dotsero in Eagle County, late Sunday morning, according to the U.S. Forest Service.

The lightning-sparked wildfire more than tripled overnight Tuesday, growing from 250 acres to nearly 850 acres, fire officials said Wednesday morning. By Thursday morning, the fire had more than tripled in size again and was mapped at 2,624 acres, fire officials said.

At least one building has been destroyed by the wildfire, according to a Thursday morning briefing from Operations Section Chief Philip Knaub. It’s unclear what type of building it was. Firefighters were able to save other buildings in the area.

The fire is growing on all sides, according to maps provided by fire officials. Flames have spread largely to the west and south, but winds pushed the fire east as well on Wednesday.

Residents of Sweetwater Road and areas along Colorado River Road from Sweetwater to Red Dirt Creek were ordered to evacuate, emergency officials said. Derby Mesa Loop remains on pre-evacuation orders.

An evacuation center with workers and resources opened Wednesday morning in Dotsero at Two Rivers Community Center, 80 Lake Shore Drive.

The U.S. Forest Service also closed parts of the White River National Forest in Eagle and Garfield counties. The closure runs from Sweetwater Lake to the north, east along the forest boundary to Derby Loop Road, northwest along Middle Derby Creek to Island Lakes and south along Island Lakes, W Mountain, Turret-Crescent and Turret Creek trails.

Bureau of Land Management lands in Garfield and Eagle counties were closed to the public on Wednesday, fire officials said. The closure includes all BLM land north and west of Gypsum, north of Coffee Pot Road, west of the Colorado River, east of the White River National Forest boundary and south of Derby Creek.

Stoner Mesa fire, near Dolores

A wildfire burning on more than 9,800 acres in western Colorado’s San Juan National Forest saw containment start to grow on Wednesday, fire officials said.

The lightning-sparked Stoner Mesa fire was last mapped at 9,872 acres in Dolores County and is 27% contained, according to a Thursday morning update.

The nearby town of Rico remains on pre-evacuation status, and parts of the national forest are closed to the public because of the fire. New pre-evacuation orders were issued on Wednesday from the edge of Dolores County along County Road 38 to the West Dolores campground, according to the county’s emergency management team.

Dry weather on Wednesday afternoon increased fire activity along the fire’s western edge, and the flames crossed Stoner Mesa Trail, fire officials said.

Crosho fire, near Yampa

The 2,067-acre Crosho fire burning on the border of Rio Blanco and Routt counties west of Yampa is 25% contained, fire officials said Wednesday night.

Fire officials estimated the Crosho fire threatened more than 200 structures, but no buildings had been destroyed as of Wednesday.

Pre-evacuation orders remain in place for multiple areas around the fire, and county roads in those areas remain closed to non-residents. Mandatory evacuation orders were lifted Monday.

Statewide impacts

Multiple air quality advisories were issued Thursday morning for wildfire smoke, particularly near the Stoner Mesa and Derby fires.

The advisories, which will be in effect until at least 9 a.m. Friday, cover western Eagle, eastern Garfield, southeastern Dolores and northeastern Montezuma counties, according to the Colorado Department of Public Health and Environment.

Smokey conditions are most hazardous for young children, older adults and people with heart disease or respiratory illnesses, state health officials said in the alert.

All residents should limit outdoor activity when heavy smoke is present. If visibility drops to 5 miles or less, the smoke has reached unhealthy levels.

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