After Sunday’s winds fanned a small fire in the Welcome Creek Wilderness, Monday’s weather helped it spread over 2,000 acres.
The Cinnabar fire, burning in the Sapphire Mountains about 15 miles up Rock Creek Road and about 10 miles east of Stevensville over the Bitterroot-Rock Creek Divide, was one of several wildfires started by a lightning-charged thunderstorm that passed over the Clark Fork and Bitterroot valleys last Wednesday morning.
Like a number of the lightning starts from that morning, it remained small and nonthreatening until Sunday when dry, breezy conditions fanned the flames.
The winds and mountainous terrain caused the fire to occasionally torch near the top of the ridge above and to the north of Carron Creek on Sunday. The fire is burning in heavy timber with a lot dead and downed trees.
On Monday, the Lolo National Forest upgraded the fire to a Type 3 incident, which brings in more resources to tackle the fire. Type 5 is the lowest category of wildfire response while Type 1 fires are the highest priority.
By the end of the day, the Lolo and Bitterroot national forests closed off certain areas surrounding the fire for the safety of firefighters and the public. Officials from the Stevensville Ranger District on the Bitterroot National Forest and the Missoula Ranger District are working together on the fire.
Sixty-five firefighters, including one hotshot crew and a Type 2 hand crew have been assigned to the fire. Ground crews have moved in to work along the Bitterroot Divide Road #2129 and the Bitterroot/Rock Creek Divide Trail #313, north of Ambrose Saddle, which will be used as key holding lines over the next few days.
Firefighters will clear vegetation to reduce fuel along these lines in order to keep the fire from burning west over the Bitterroot Divide. These roads and trails are outside of the Wilderness boundary.
Crews are laying hoses along parts of the Bitterroot/Rock Creek Divide Trail #313 to further strengthen fire line. A helicopter is available as needed if hotspots flare up within the perimeter of the fire.
Fire behavior was active as temperatures rose on Monday afternoon, and the smoke added to that already flowing northeast from California. Monday’s weather was warm and dry with west winds, which stoked the fire.
Due to low visibility from the smoke that has blanketed southwestern Montana for a few days, air operations did not occur until the early evening. But firefighters could see that the fire was spreading mostly to the north, northeast and southeast, away from the Bitterroot Divide and into the Wilderness.
The fire is making short runs up steep slopes and torching is visible in several stands. The fire perimeter is approximately 3 miles west of the bottom of Rock Creek.
Sometimes, fires are allowed to burn in wilderness areas to allow natural processes to occur and to save firefighting resources as long as no structures are threatened. There are no structures threatened at this point.
Several areas nearby have already burned in previous years, and they can act as natural barriers to slow wildfire growth. These include the Cooney Ridge Fire (2003) directly to the north of the fire; the Sawmill Fire (2007) down to Rock Creek east of the fire; and Harry’s Flat Fire (2013) to the southeast.
Contact reporter Laura Lundquist at firstname.lastname@example.org.