Torching and crown runs were reported as the fire crossed the Jones Creek Trail and the Hermosa Creek Trail, but not the Hermosa Creek drainage.
As many as 1,300 homes have been evacuated. The Fire Weather Potential Index is listed as "high".
La Plata County's latest order follows the evacuation of more than 1,000 homes earlier along U.S. Highway 550, a key artery connecting the cities of Durango and Silverton, roughly 135 miles (217 kilometers) northwest of the Four Corners Monument that connects Colorado with Utah, Arizona and New Mexico.
A mandatory evacuation order was issued for 220 residences in the Falls Creek Ranch and High Meadows subdivisions and for residences on the west side of County Road 203 between Trimble Lane and Cometti/Mead Lanes on Saturday, La Plata County Government said.
The fire is about a quarter of a mile from the nearest house, and fire officials said structure protection is in place.
Aerial operations are creating a larger burnout area on the north side of the fire to serve as a barrier should the fire spread that direction from the southwest.
Aircraft are monitoring the fire's west flank.
With dry, windy weather in the forecast Sunday, firefighters said they expect the fire to continue to grow.
Firefighters have kept the Colorado fire to the west of Highway 550 and away from structures, county commissioners in La Plata County, Colorado, said in a Saturday Facebook post. No structures had been lost as of Friday morning.
The so-called 416 Fire in southwest Colorado had burned almost 17,000 acres by Sunday morning, an area larger than Manhattan.
The Type I team managing the 416 Fire will also assume command of the Burro Fire at 6 a.m. Monday and a separate camp will be set up for management of the Burro Fire. Gusts are expected to be between 15-20 miles per hour at the fire, and Durango is expecting a high of 84 degrees, said Michael Charnick with the National Weather Service in Grand Junction.
The fire started June 1 in the San Juan National Forest but the cause hasn't been determined. It was 10 percent contained.
But officials said winds should drop on Monday (June 11) leaving smoke heavy and low in the valley and visibility restricted. Fire officials said in the Saturday update that Highway 550 was closed from mile marker 32 to 47 and pilot cars were escorting traffic through there.