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Trail Ridge fire threatens Sula evacuations; other fires burn as smoke lingers

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"We have a lot of clouds over Idaho and western Montana, but you can see smoke in Washington and Oregon," said Sarah Coefield, Missoula's air quality specialist, of this satellite image from an update Tuesday.

The Trail Ridge fire southeast of Sula continued to push north toward private property as fire managers and the Ravalli County Sheriff’s Office evaluate trigger points for evacuation warnings east of Sula. 

The fire grew to 17,043 acres by Tuesday morning, a significant expansion from 10,874 acres a week prior, with slowed growth to the east near Shultz Saddle Road (Forest Road 725) and increased growth north toward Mink Creek Saddle and, farther north, East Fork Road east of Sula. The lightning-caused fire, burning about 5 miles southeast of Sula and just north of the Idaho-Montana line and along the Ravalli-Beaverhead county line, was 18% contained Tuesday with 217 personnel assigned. The fire was discovered Aug. 26.

Fire managers and the Sheriff's Office are monitoring fire growth to the north as the fire nears an action point for evacuation warnings. 

"As the fire nears the indirect lines constructed paralleling the East Fork Road, the fire is still within containment lines and has not reached the Action Point identified for the 'Warning' stage of the Evacuation Plan at this time," fire managers stated Tuesday. "As the fire nears this Action Point, Fire Managers and the Ravalli County Sheriff’s Department are prepared for the possibility of moving into this 'Warning' stage."

Ravalli County's evacuation plan is available at Fire managers and local officials scheduled a public meeting for 7 p.m. Tuesday at the Sula Clubhouse. 

Although the fire is within 2 miles of U.S. Highway 93 on the fire's western side (the fire is east of the road), fire managers on Tuesday morning didn't project much fire growth to the west, south or east over the next two days, instead anticipating growth "primarily to the north." 

The fire reached an action point for back-burn operations Monday, according to fire managers, but winds didn't allow the operation to proceed. In a back burn, firefighters thin fuels between a containment line and a wildfire, and then burn from the line back toward the wildfire, depriving the wildfire of fuels and, ideally, stopping the fire front short of the containment line. In some situations, crews on the ground or overhead will ignite larger fires closer to the fire front. The larger fires are intended to draw back-burn flames along a containment line in toward the wildfire with the winds generated by the larger flames. 

Smoke lingers

Smoky, unhealthy air persisted through rain and the departure of an air-trapping high-pressure ridge on Tuesday, but some relief could come Wednesday. 

Air in Hamilton clocked in at 203 on the 500-point Air Quality Index scale at 11 a.m. Tuesday, just 3 points into the "very unhealthy" category. The measurement was down from a peak of 308 — classified as "hazardous," the most severe of five categories — at 9 a.m. Monday. But Tuesday's air was still far smokier than just a few days prior: Daytime air quality in Hamilton mostly hovered between 150 and 185 AQI last week and dropped below 100 three nights, even measuring 38, or "good," at 11 p.m. Friday.

Monday morning's hazardous air in Hamilton was the worst air quality measurement seen there so far this year, and air quality consistently improved, if only slightly, starting around noon Monday.

No relief from peak smoky conditions had come to Missoula by midday Tuesday, when air quality measured 181 at 11 a.m. — a new low point for air quality this year and 1 point worse than Monday's 5 p.m. peak of 180. Air in Missoula had been consistently stuck in the "unhealthy" category since 5 p.m. Sunday. Missoulians had a brief respite from smoke-choked skies Friday through midday Saturday when an uncharacteristic west-moving cold front came into the area from the east, over the Continental Divide, and pushed smoke out of the area and back over Idaho to the west. 

Some relief could come Wednesday, when winds from the west and southwest could push a stagnant mass of inversion-trapped smoke out of the area, according to Sarah Coefield, an air quality specialist with Missoula City-County Health Department, and Travis Booth, a meteorologist for the National Weather Service in Missoula. But overhead air that itself may be filled with smoke could blunt the clearing effects of transport winds from the west. And those transport winds aren't very strong. 

"We’re out from under the nexus of the high-pressure ridge," Coefield wrote in an emailed update Tuesday, "and this morning’s Missoula inversion was considerably weaker than any I’ve seen lately, which means we’re likely to see more atmospheric mixing today than we have since Saturday." But, she cautioned, "atmospheric mixing is best when there is clean air to mix down to the valley floor."

"Unfortunately, we have generally sluggish overhead winds and I’ll be honest, I have no idea how much overhead smoke we have or how evenly distributed it is across the county. Cloud cover is all kinds of inconvenient for smoke forecasting." 

There are no "valley scouring winds" in the forecast, Coefield wrote. But even if such winds did fully eject the smoke lingering in valley floors, that would revert the Missoula Valley back to its ongoing smoke concern: being at the mercy of active fires upwind from the valley. 

That's the case in the Bitterroot Valley, where the Blodgett Lake and Mill Lake fires have been spilling smoke into the valley as they burn in adjacent canyons on the east side of the Bitterroot Mountains (west side of the Bitterroot Valley) just northwest of Hamilton. According to the Bitterroot National Forest, a Type-I incident management team, the most robust configuration of the interagency incident management teams assigned to manage wildfires, has been ordered to manage both fires, which are about 2.5 miles apart. 

By Monday, the Mill Lake fire had grown to 1,608 acres, burning primarily in timber and heavy downed fuels on a southeast-facing mountainside in the upper reaches of the Mill Creek drainage, just northeast and downstream from Mill Lake, about 12 miles west of Corvallis. The lightning-caused fire started Aug. 29 but began growing significantly during hot, dry, windy conditions Sept. 3. But the fire has grown minimally in recent days, mostly with isolated hot spots and smoldering. The Blodgett Lake fire was 1,200 acres on Monday after exhibiting "extreme fire behavior" on Sunday, fire managers stated. The fire, reported Aug. 25, is burning through timber, upright dead trees and blown-down trees in the valley floor along Blodgett Creek about 11 miles west of Hamilton and about 1.8 miles down the Blodgett Creek drainage from Blodgett Lake. 

Other fires have grown

North of Missoula, the Boulder Lake fire reached 1,800 acres by Tuesday, primarily from growth to the south. The fire, caused by lightning and discovered Sept. 3, ballooned from 300 acres to 1,400 acres amid critical fire weather Sept. 7. By Tuesday, the fire reached the Boulder Lake Trail (No. 333). Structure protection and water drops from helicopters had thus far preserved the Gold Creek Cabin, according to fire managers with the Lolo National Forest and Montana Department of Natural Resources and Conservation. Cooler weather Tuesday and higher humidity this week were expected to moderate fire behavior. The fire started in the Rattlesnake Wilderness Area but grew beyond the wilderness and onto regular Lolo National Forest lands. 

"Fire managers continue to utilize a confine and contain suppression strategy to engage the south and eastern flanks of the fire, outside of the Wilderness boundary," according to an update Tuesday. "Containment opportunities will continue to be assessed and may include existing burn areas, natural barriers, trails, and existing road systems."

Boulder Lake, Fly Lake and Gold Creek Lake are closed, as are trails and roads accessing those areas. Complete closure information is available at

In central Idaho, the massive and long-burning Moose fire reached 127,500 acres by Tuesday, with 37% containment primarily on the west, north and east sides of the fire. The fire, burning northeast and east of Salmon, is largely uncontained on its south and southeast sides, nearest to Salmon and the town's municipal watershed. On Tuesday, 918 personnel were working the fire, including 21 hand crews and 47 engine crews, aided by seven helicopters. The fire was caused by humans on July 17 about 5 miles west of North Fork, Idaho. 

The fire made an aggressive run toward Salmon last Tuesday and Wednesday, Sept. 6-7, prompting evacuation orders for areas on the town's northwest outskirts. Flames were visible in town throughout the night Sept. 7-8 as residents in the area communicated in Facebook groups to share information on evacuation orders issued around 10:30 that night. The fire grew by more than 15,000 acres during the two days leading up to the evening of Sept. 7, driven by 40 mph winds overnight and burning into the northern reaches of Salmon's municipal watershed. 

The fire has grown about 4,900 acres in the week since then. Areas around the Beartrack Mine and Leesburg, north of Cobalt and west of Salmon, remain under an evacuation order. Evacuation orders around Salmon were lifted. 

Cloudy, rainy conditions Tuesday were expected to temper fire activity, but thunderstorms and their resultant winds could aggravate burning at times. 

Webcamera images from Glacier National Park and the Montana Department of Transportation show much of Montana is smoked over. (images from Sept. 12, 2022)

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Outdoors Reporter

Joshua Murdock covers the outdoors and natural resources for the Missoulian.

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