Aug. 21, 2026: Wildfire Smoke Air Quality Update

The current air quality across Missoula County is Moderate to Unhealthy for Sensitive Groups. See current air quality conditions at Fire.AirNow.Gov.

Hot temperatures and gusty winds continue to increase fire activity across the region today. West winds have blown smoke in from nearby fires like the Moose Mountain, Grotto, Cascade, and Cherry Peak fires, and from other fires further away in Oregon, Washington, and British Columbia. The Deer Creek Fire near Happys Inn, Montana started yesterday and expanded rapidly, and it may have smoke impacts on Northwestern Montana.

Of the nearby fires, the Moose Mountain Fire in Idaho, northwest of Lolo Pass, has had the most smoke impacts on Missoula County. Areas on the Western side of the county that are nearest to the fire have experienced the most localized impacts. In general, expect diurnal patterns of worsening air quality overnight as smoke settles into the valleys and improvements throughout the day as increased dispersion helps the smoke lift and mix out of the valleys.

For example, as the smoke settled into the valleys last night a couple of air quality sensors in the Lolo area reached Unhealthy for Everyone or Red on the Air Quality Index. The same thing happened near Frenchtown two nights ago, likely due to a slightly different wind direction. As air dispersion and mixing increased this afternoon, air quality has improved and sensors in the Lolo area now range from Moderate to Unhealthy for Sensitive Groups. In most other areas of the county, air quality conditions remain at Moderate.

Air quality conditions from EPA Fire and Smoke map on Friday, Aug. 21.

This evening, winds are forecast to shift to blow out of the east for several hours, which will likely help improve air quality conditions. Dry thunderstorms are possible tonight. Tomorrow, showers and thunderstorms are forecast throughout the afternoon and evening. The clouds, rain, and cooler temperatures will likely help ease fire activity and smoke production at nearby fires and likely improve air quality conditions. However, lightning could spark new fires across the region.

A cold front on Saturday night will bring cooler temperatures on Sunday. However, it will also bring a very dry air mass and strong west winds, which will create elevated fire conditions. Any fire starts from Saturday could become very active on Sunday. Increased fire activity and smoke production will likely lead to worsening air quality conditions. Next week, the forecast has us back under high pressure, with warm temperatures, dry conditions, and southwest winds, which will likely bring continued smoke impacts.

HRRR model near-surface smoke forecast for noon, Saturday, Aug. 22, showing light smoke over Missoula County.

In general, this weekend we can expect variable air quality that could change rapidly at times. Periods of Good to Moderate air quality are likely, but poor air quality is also possible, especially in localized areas. Many factors are at play, like wind direction, wind speed, rainfall, clouds, lightning, fire activity, diurnal patterns, and others. With variable and frequently changing air quality conditions it’s extra important to regularly check current conditions at Fire.AirNow.Gov so you can make the best decisions for your health. If conditions are changing fast, check out the Hourly PM2.5 and Sub-Hourly graphs to get the latest data from each sensor. Take a look at this handy Air Quality Index Activity Guide for guidance on what to do at each level of the Air Quality Index.

If air quality worsens, remember that creating a clean indoor air space is the best way to reduce your exposure to smoke. You can either use a portable air cleaner with a HEPA filter or a MERV 13+ furnace filter attached to a box fan. For more information about ways to keep smoke out of your living space and reduce your exposure to smoke, explore the resources at MontanaWildfireSmoke.org.