Bitterroot Valley Wildfire History and What It Taught Homeowners

How often did the Bitterroot burn before 1900?

Often. At a 2014 Northern Rockies Fire Science Network field trip on the fires of 2000, retired Forest Service research forester Steve Arno described the valley's historic dry forests as dominated by large, widely spaced ponderosa pine on north and south slopes up to about 6,000 feet. He said burning by Indians was common, and that before the 1900s these forests burned an average of 10 times each century.

Montana DNRC's west-central Montana landowner guide gives the same picture for the wider region: ponderosa pine and western larch forests historically experienced mixed severity fires every 10 to 30 years, which kept the forest open and favored thick-barked, fire-resistant trees, while Douglas-fir dominated forests saw low to moderate severity fire about every 45 years. Ravalli County's 2024 wildfire protection plan puts the historic fire return interval for ponderosa pine woodland and savanna at three to seven years. Big fire years happened too: the county plan records 112,866 acres burned in the 1880s, compared with 8,013 acres in the 1890s.

What did the 1910 fires mean for the valley?

Ravalli County's plan notes that the Great Burn of 1910 reached the Bitterroot Valley. Missoula County's 2018 wildfire plan describes the scale of that summer: 78 firefighters and an unknown number of citizens died, and five towns and three million acres burned in Montana and Idaho. It says the fires influenced America's wildland fire policies for most of the 20th century.

Those policies were built around putting every fire out. Ravalli County's plan says aggressive 20th century suppression reduced acreage burned for a time but caused a buildup of fuels that has increased fire frequency and severity in modern times. Arno described the change on the ground: with fire excluded, Douglas-fir and grand fir, which frequent fire had kept in check, established and grew within and among the ponderosa pine. Our guide to Douglas-fir encroachment explains why that matters.

What happened in the fires of 2000?

The setup was a dry winter. The Fire Science Network's summary reports that the winter of 2000 brought below average moisture, low elevation sites on the Bitterroot National Forest lost their snowpack in early February, spring rains grew abundant grass, and by summer live fuel moistures were as much as 75 percent below normal. Dry lightning on July 31, 2000, started approximately 100 fires. High temperatures, very dry fuels and occasional high winds merged large and small fires into big complexes.

The Forest Service's own summary says more than 356,000 acres of national forest, state and private land burned, nearly a third of it at stand-replacing intensity. Seventy homes and 170 other structures were destroyed. It also records what did not happen: 55,000 acres of wildland-urban interface burned but 124,000 did not, more than 1,700 homes were successfully protected, and of well over 10,000 firefighters who worked in the valley that summer, none were killed or seriously injured. The President issued a disaster declaration for Montana.

What did the 2000 fires teach homeowners?

Three lessons stand out in the sources. First, overcrowded forests and drought together let fire run: the Forest Service summary names extended drought and overcrowded forest conditions as the reason the fires ran unchecked. Second, homes could be saved where firefighters had room to work, and lost where they did not. Third, the burned ground kept causing trouble after the fire: the Fire Science Network summary reports debris flows were most common on severely burned sites where much of the granitic soil was exposed, and the recovery included erosion barriers on more than 4,500 acres and hundreds of culvert projects.

The field trip also recorded a policy lesson about firefighter safety. Retired Forest Service fire specialist Sonny Stiger described county resolutions he helped pass in western Montana to prioritize fire protection that reduces threats to firefighters, train county fire staff in fire behavior, prohibit homes in the WUI from dictating suppression tactics, and support fuel mitigation that improves structure survivability and firefighter safety. A homeowner who has done the work around the house makes it possible for crews to defend it; one who has not may be passed by. See erosion and flooding after a fire for the after-fire side.

What happened in the Roaring Lion Fire?

The Roaring Lion Fire started on the Bitterroot National Forest on July 31, 2016, sixteen years to the day after the lightning that began the fires of 2000. A post-fire assessment by Bitter Root Resource Conservation and Development says it burned east with high intensity from national forest land into the wildland-urban interface in the Roaring Lion, Judd Creek Hollow and Sawtooth drainages on the west side of the valley, and that within a four-hour period it consumed over 3,500 acres and burned 16 homes and 49 outbuildings. Ravalli County's plan lists its final size as 8,658 acres.

The assessment looked at 21 private properties inside the perimeter that had completed fuel reduction projects over the previous decade, about 230 acres in total, mostly funded through a Western States WUI grant administered by Bitter Root RC&D. The projects aimed for 10-foot crown spacing, pruning to 8 to 10 feet and reduced surface fuels. Its summary records homes surviving on 11 of those properties and destroyed on 8, and lists ember showers as a factor at every property where structures were lost.

What did Roaring Lion teach about fuel reduction?

That fuel reduction changes how a fire burns, and the ground around the buildings decides what survives. The property notes describe thinned stands where fire stayed as an intense surface fire with minimal torching, an intact mature ponderosa stand that survived with a moderately intense understory burn, a house that survived a crown fire passing to its north partly because of a large open area on the side the fire came from, and a property where open and thinned ground around the home and outbuildings is credited with their survival.

They also describe losses on treated land: a shop and equipment burned by surface fire and embers while the house survived, and homes destroyed by ember showers and surface fire where the immediate surroundings were not cleared. Several notes mention one way in and one way out, with or without a turnaround. The lesson is to treat both scales: thin the stand, and also clear the home ignition zone around every building, and plan driveway access.

What happened in 2017 and since?

Ravalli County's plan lists the Lolo Peak Fire of 2017 at 53,801 acres and the Meyers Complex of 2017 at 62,034 acres; both started in neighboring counties and crossed into Ravalli County. The plan describes 2016 and 2017 as particularly intense fire years for Ravalli and neighboring counties. Missoula County's plan says more than 230,000 acres burned in Missoula County in 2017, almost four times the next largest year in its 20-year record.

The longer trend is in the same direction. Ravalli County's plan says more than 500,000 acres burned in the county from 2000 to 2019, that wildfires there are increasing in size and intensity, and that human-caused ignitions start the majority of fires, especially in the WUI: in 2023, 62 percent of the county's wildfires were human caused.

How did the Bitterroot change its planning after these fires?

The Forest Service summary describes the Hayes Creek project, a fuel reduction treatment on 700 acres identified as a priority under a community fire plan, as one of the early responses. Ravalli County published a community wildfire protection plan in 2006 and a revised plan in 2024 that redrew the wildland-urban interface, added a Community Protection Zone based on Forest Service fire simulation modeling, and identified West Fork and Painted Rocks as at-risk communities.

Private landowners have been part of it through cost-share programs like the one behind the Roaring Lion projects. Our guides to the wildland-urban interface in Missoula and Ravalli counties, Ravalli County fire districts and resources and fuel reduction cost-share programs cover where things stand now; programs change, so confirm details with the agency.

What should a Bitterroot homeowner take from this history?

That large fires will come again, that they tend to start on public land in a dry summer and run toward the valley, and that the outcome for a given house is decided mostly by what is on and around it. The fires of 2000 showed that defensible space lets firefighters protect homes. Roaring Lion showed that thinning changes fire behavior but that embers and the immediate surroundings decide which buildings burn.

HJ Property Care is based in Florence and does fire mitigation up and down the valley: ladder fuel removal, selective thinning, limbing and near-structure cleanup, with slash chipped or hauled. This guide is part of our Montana Wildfire Guide; the Bitterroot Valley service area page lists the towns we cover.

Call HJ Property Care & Tree Service at (406) 215-7319 or request a free estimate and we will walk the property with you.

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