Weather window: Lolo crews launch high-priority burn up Butler Creek

Crews with the Lolo National Forest work their way down slope, setting fire to the understory as part of a prescribed burn conducted Wednesday up Butler Creek on the Missoula Ranger District. Within a few minutes of this photo, the smoke was too thick to see the crews. (Martin Kidston/Missoula Current)

By Martin Kidston/Missoula Current

Under clear skies and a soft breeze, crews with the Lolo National Forest slipped into the woods and lit their drip torches shortly before noon on Wednesday, setting fire to the understory as part of a prescribed burn years in the making.

The weather window had parted the day before, giving crews roughly 48 hours to burn off 80 acres of vegetation in an area deemed by Missoula County fire officials to be a high priority up Butler Creek, just two miles short of Snowbowl.

“It’s the number one priority area in the county’s Community Wildfire Protection Plan,” said Jennifer Hensiek, the Missoula district ranger for the Lolo National Forest. “It gives us the ability to have more defensible space, both on the forest land as well as the private land.”

Members of the crew had gathered on Snowbowl Road earlier in the day to begin their fire briefing, the sun still tucked behind the ridge above.

Standing around a topographical map of the burn zone, acting burn boss Stryker Clark rolled through the objectives – reduce one-hour fuels up to 50 percent, retain snags for wildlife, expose bare soils to a minimum of 15 percent, and keep out of the riparian area below.

“Flexibility is going to be big on this,” Clark told his crew. “The longer we wait in the day, we’ll get more heating and better drying of the fuels. With that being said, we want to have ignition ceased by 1700 to give the smoke some time to clear out.”

Stryker Clark, who served as acting burn boss on Wednesday, reviews the prescribed fire’s objectives during a morning briefing with Lolo National Forest crews on Snowbowl Road. (Martin Kidston/Missoula Current)

While planning a burn to improve forest health and reduce the risk of a major wildfire near Missoula’s urban interface took years of planning, and finding a weather window suited for the project required patience.

The plan itself dates back to 2012, and Wednesday’s burn marked just the third time crews had entered the zone to tackle the work. Approval for the burn came only the day before, giving crews little time to prepare for a job that would require long hours in steep terrain under a warming May sun.

“Once we get a window and we get smoke approval, it’s my job to start planning the implementation of it,” said Clark. “That plan is years in the making. It lays out how we operate, what resources we need to have, and while it gives us room to adjust on the ground, it sets out some pretty firm guidelines as well.”

Permission to conduct a burn in and around Missoula is a complicated process that requires a number of favorable weather conditions, and final approval from the Montana-Idaho Airshed Coordinating Group, as well as Missoula County.

For each planned burn, fire officials must describe the type of burn they plan to conduct, the number of acres and the elevation of the burn. The airshed coordinator, working in conjunction with a meteorologist, then places restrictions on the burn according to atmospheric weather conditions.

This day’s burn was conducted at 4,545 feet in a southwest-facing drainage. The maximum temperature was forecast at 75 with 22 percent humidity, variable winds at 5 mph, and a mixing height for the smoke at 5,500 feet.

The required information and subsequent weather window looks to reduce smoke in the valley below.

Crews began the prescribe fire by setting smaller fires to test the weather and fuel conditions. (Martin Kidston/Missoula Current)

“We have to have smoke parameters open up for us, since we’re in a pretty restricted airshed here,” said Jesse Kurpius, fire management officer for the Missoula Ranger District. “There’s a lot of planning and it starts years in advance. Yesterday, we just got smoke approval.”

With smoke approval granted, Kurpius considered the project’s primary goal. Among other things, the prescribed burn looks to treat the forests with natural fire and, by doing so, reduce the risk of a catastrophic blaze at a later point in time.

By burning off the smaller fuels, crews may better manage a wildfire and keep it out of the forest canopy. It’s there, up in the treetops, where many summer fires explode in size and make devastating runs over great distances.

Kurpius admits that such a fire could prove catastrophic for the hundreds of property owners and residents living in the drainages north of the Missoula Valley. It’s why this particular prescribed burn was named as one of Missoula’s highest priorities.

“We’re trying to treat both sides of this drainage, with the huge population in Grant Creek and Rattlesnake Creek,” said Kurpius. “A lot of our weather comes from the west and we have drainages that align with that, and they run right through the urban interface.

“By doing this, we’re putting less risk to private property and homes, and our firefighters.”

Contact reporter Martin Kidston at info@missoulacurrent.com