Planned burnouts on western flank of fire put on hold
By Bob Berwyn
SUMMIT COUNTY — A Red Flag fire warning for the High Park Fire area and most of western and central Colorado has prompted fire officials to temporarily shift tactics in the battle to control the western edge of the 55,000-acre wildfire in Larimer County.
Previously planned burnout operations to reduce fuel in the fire’s main path will be on hold, incident commander Bill Hahnenberg said during a media briefing Saturday afternoon, explaining that firefighters instead will focus on holding and reinforcing existing containment lines.
Crews have made big strides in controlling the fire the past few days, achieving 45 percent containment; the changing weather conditions will test those fire lines and present new challenges for the more than 1,600 firefighters at the scene. The winds will also make aerial operations difficult, if not impossible at times.
A strong jet stream sinking down from the northern Rockies could generate steady west winds from 15 to 25 mph, with gusts up to 50 mph, combining with low relative humidity to create dangerous fire weather conditions throughout much of the area.
According to the National Weather Service, the winds could lead to extreme fire behavior at fires already burning and make any new fire starts difficult to control, with high rates of spread.
“Our intent was to do backfires with aviation,” Hahnenberg said, referring to the process of lighting fires from the air with helicopters to eliminate fuels in the fire’s path along the west flank, where the High Park Fire is still burning uncontrolled along a lot of its perimeter.
But the forecast west winds could drive the fire back toward the east.Hahnenberg said that’s called a backing fire.
“For the most part, that doesn’t burn as intensely or move as quickly … but it still moves,” he said. “What we’re really worried about is these corners getting hot, then getting a large wind and getting a big run.”
Hahnenberg described several scenarios under which a backing fire could become dangerous to firefighters — and to homes in the area, for example when a smoldering log rolls off a ridgetop and ignites a new fire at the base of steep slope or ridge. With the forecast strong winds, such an ignition source could spark a fast-moving fire up the steep slopes, or even a crown fire in places with available fuel.
“We don’t want to add any fire to the area … hotter, more extensive fire spread across the landscape is not what we want … We can’t hurry and fight the fire effectively,” he said.