Missoula wildfire smoke forecast
The map above shows NOAA HRRR-Smoke near-surface PM2.5 for the next 48 hours, updated hourly, with active fires from NIFC and live AQI from EPA AirNow monitors. It opens over Missoula.
Missoula sits at about 3,200 feet where five valleys converge, ringed by mountains on every side. It is one of the most effective cold-air traps of any city in the West, and the same geometry that gives it a famous winter inversion problem gives it a smoke problem every August.
Where the smoke comes from
The Lolo and Bitterroot national forests are immediately west and south, and the Frank Church and Selway-Bitterroot wilderness areas beyond them are among the most fire-active country in the lower 48. Smoke from those fires drains into the Missoula valley overnight, so the city can be in hazardous air with the nearest fire still tens of miles away.
How long it lasts
Slowly. The valley holds what settles into it, and a light afternoon breeze is often not enough to turn the air over. Missoula episodes are measured in weeks rather than days, and the practical question is usually which hours of the day are tolerable rather than when the smoke will be gone.
Past smoke events
August and September 2017, driven by the Lolo Peak and Rice Ridge fires, gave Missoula more than a month of unhealthy-to-hazardous air and became the reference season locally. The 2000 season and August 2021 were comparable.
Running, riding, and trailheads
The Mount Sentinel M trail, the Rattlesnake, and Blue Mountain all start in the valley and climb out of it. Sentinel gains about 600 feet in under a mile, which on a trapped morning is often the difference between the inversion and the air above it.
Reading the map
Use the layer toggle to compare NOAA HRRR-Smoke with the ECCC FireWork model. When the two disagree, treat the higher reading as the cautious call.
Near-surface is the product that maps to what you breathe and to AQI, not the high-altitude column that only tints the sunset. A sky that looks bad and a monitor that reads fine are usually both correct, and they are describing different layers of air.