Wildfire is a naturally occurring phenomenon, and many ecosystems rely on fire at regular intervals to clear the forest floor, kill disease, and allow new plants to establish. In our region, the frequency and severity of fires vary over forest types and location. Over the last century, the policy of attempting to suppress  wildfires has, in some areas, resulted in denser forests that, when they burn, do so much more intensely and destructively than they might have in the past. At the same time, expansion of the Wildland-Urban Interface (WUI) and increased development in the WUI put more people and structures at risk from wildfire. As Missoula County's climate warms and as summers become drier, wildfires are likely to increase in size and frequency and the fire season is likely to become longer. 

More wildfires in Montana and the west, and a longer wildfire season, will mean more days of unhealthy air quality for Missoula County residents. 

As the average temperatures rise, the average number of hot days (> 90°F) per year is projected to increase 12-20 days by 2050. By mid-century, Missoula County’s average annual temperature is projected to increase by about 3-5°F, with the greatest temperature increases projected to occur in July, August, and September.

Climate projections indicate that Missoula County is likely to experience increased year-round precipitation. Because year-round temperatures will be higher, more precipitation will fall as rain rather than snow, especially at low elevations. Throughout Montana’s history, rain-on-snow events have caused the most severe and destructive floods. Some evidence suggests that warm and wet winter storms originating in the Pacific Ocean will become more severe in the future, likely bringing more rain-on-snow events to Missoula County. Extreme precipitation events (intense rain) are another common cause of flooding in Montana, and climate models project increases in the frequency and magnitude of the most intense precipitation events. Additionally, severe wildfires can increase the risk of flash flooding resulting from rainfall runoff over burned areas.

Climate projects anticipate that summers will be significantly drier. Higher temperatures are projected to reduce low-elevation snowpack, early snowmelt, and an earlier peak in spring runoff. Over the past half-century spring runoff has shifted at least a week earlier in the northern Rockies, and this trend is likely to continue as the climate continues to warm. Earlier snowmelt and decreased summer precipitation are expected to reduce late-summer streamflows across the county. There is widespread agreement that long-term droughts will be more severe when and where they do occur. 

One plausible future scenario for Missoula County includes a significant increase in year-to-year climate variability. While variability and unpredictability will affect all sectors, agriculture, recreation and tourism will find it particularly difficult to adapt to these conditions. We may experience some very wet years and other intense drought years, with the concept of a “typical” year simply no longer being meaningful.