As of Sunday night, the Decker Fire reached 6,300 acres, employing 882 firefighting personnel amid another red-flag warning. Containment remains at 5 percent.
Public Information Officer Shawna Hartman said work continues on all areas of the fire.
The red-flag warning was issued about 3 p.m. Monday. The warnings occur when winds, temperatures and humidity combine to create increased fire danger.
Operations Chief Mark Delmerico said crews will try to keep the fire away from “values at risk:” people, property and infrastructure. He said they will not try to get the fire to 100 percent containment.
Hartman said if winds align with drainages, an unstable air mass over the fire could result in a fire plume.
In the past few days, heavy smoke was “sheared” by brisk winds, she said, which did not allow for the formation of a plume.
Because of the relatively mild winds Sunday, Hartman said crews were able to work directly on fire lines.
Dozer and hand lines have been created on the fire’s north end on Methodist Mountain.
The fire glow was obvious again Sunday night, Hartman said, because a “thermal belt” hung over the fire. A thermal belt is warm air that gets trapped over the fire.
Normally, a fire lays down with somewhat higher humidity at night, resulting in reduced fire activity. But with a thermal belt layer over the fire, it remains active.
The thermal belt, plus low humidity carrying over from earlier Sunday resulted in the fire being active through the night into early Monday morning.
Hartman said the unstable air mass over the fire could provide “a lot of lift into the air.” A smoke plume could result.
Hartman said with the mild weather Sunday, crews were able to work right along edges of the fire with hot-shot crews, dozer and “brushing” to improve fire lines.
“If we see containment go up, it would be along that northern boundary,” Hartman said.
Work continues on contingency lines on the west side of the fire in Saguache County in the San Luis Valley.
The fire in the Sangre de Cristo Wilderness, she said, is in really rugged terrain.
“If the fire comes out of the wilderness,” she said, “there would be a higher potential for success because the indirect lines would help slow the spread” where crews could engage the fire directly.
Hand crews are working to create lines on the Rainbow Trail.
She said work was done Monday around Howard to protect homes. Crews laid out water tanks, pumps, fire hoses and sprinklers to protect homes should the fire spread to the east.
The Decker Fire started with a Sept. 8 lighting strike in the Decker Creek drainage of the Sangre de Cristo mountains roughly 5 miles southeast of Poncha Pass in the Sangre de Cristo Wilderness Area of the Rio Grande National Forest. It subsequently has spread into the San Isabel National Forest.