Assessing And Adaptively Managing Wildfire Risk in the
Wildland-Urban Interface for Future Climate and Land Use Changes

Study Area

Map of Montana The project area includes the WUI in Flathead County, Montana (shaded area on Montana map to the right). The land area of the county is about 13,605 km˛ (approximately the size of the State of Connecticut) of which 70% is publicly owned and 30% is privately owned. Average annual temperature is 5.9 °ēC (averaging 2.2 °ēC in the winter and 25.6 °ēC in the summer), average annual rainfall is 419 mm, and average annual snowfall is 1,402 mm. Elevations in the county range from approximately 900 m to 3,000 m. These conditions results in a range of vegetation communities that are representative of the Northern Rocky Mountain Forest-Steppe Coniferous Forest-Alpine Meadow ecoregion province. Dominant forest types in the county are dry montane (< 914 m), moist montane (914 m - 2,134 m), lower subalpine (1,524 m – 2,134 m), and upper subalpine (> 2,134 m). Fire, insect damage, and windthrow are the dominant natural disturbances in the four forest types. The dominant historical fire regimes in Flathead County are: moderate-frequency, mixed-severity with a fire-return interval of 30-100 years; and infrequent, mixed-severity with a fire-return interval of more than 100 years.

Flathead County was selected as the project area because it demonstrates well the challenges facing Western communities that have high growth rates in the WUI and are expected to experience significant future climate change. Specifically, the county: (1) currently has nine communities and one highway corridor at risk from wildfire; (2) has experienced several large, intense wildfires in recent years; (3) ranks eighth among all counties in the 11 western states and first among all counties in Montana in the amount of developed land in the WUI that contains homes; (4) ranks nineteenth among counties in the 11 western states and fourth among counties in Montana in the amount of undeveloped land in the WUI; (5) is located at a northern latitude (i.e., 48.3° N), making it highly vulnerable to climate disruption and large wildfires; and (6) is expected to experience substantial increases in residential development due to continued rapid population and economic growth. In addition, two of the co-PIs (Prato and Fagre) have conducted related studies in the county (Prato 2005c; CARES 2007ab; Prato and Fagre 2007), the results of which will be used in the project; and several key federal, tribal, state, and county agencies have agreed to serve as institutional collaborators (see section 6).

From 1990 to 2000, the total population of Flathead County increased 25.8% to 74,471, compared to 12.9% for the state of Montana and 13.1% for the nation. Between April 2000 and July 2005, county population grew 11.7%, compared to 3.7% for Montana and 5.3% for the U.S. Estimated county population was 83,000 as of July 2005. The population is projected to reach 113,140 by 2025). About 75% of the population resides outside the incorporated areas. In the last 30 years, 42,998 ha of farmland in the Flathead Valley have been converted to developed uses, and ranchland in the county is at risk of being converted to low-density residential development. The area in the WUI is increasing as residential development expands into wildland areas of the county.