Glacier National Park 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 Glacier National Park.
Glacier is built of steep, narrow valleys separated by the Continental Divide, with the Lake McDonald valley on the west side and the Saint Mary valley on the east. Those valleys hold smoke exceptionally well, and the Divide often separates two genuinely different air masses, so the west and east sides of the park can report different conditions on the same day.
Where the smoke comes from
Fires within the park and in the surrounding Flathead country produce the most severe smoke, and transport from Idaho, western Montana, and southeastern British Columbia supplies the regional haze. August and September are the peak, and the park's west side is closer to the sources.
How long it lasts
Valley pooling releases through the morning as the slopes heat and upslope flow develops. Regional smoke that has filled the whole Flathead basin is far more persistent and can last for weeks. West-side clearing typically lags the east side.
Past smoke events
The 2017 Sprague Fire burned the historic Sperry Chalet and filled the Lake McDonald valley for much of the season. The 2003 Robert Fire and the 2018 Howe Ridge Fire both burned along Lake McDonald and closed sections of the park.
Trails and viewpoints
Going-to-the-Sun Road climbs from the valley floor to Logan Pass at 6,646 feet, which on a pooled morning means driving up out of the smoke. The Highline Trail and the Many Glacier valley sit on the drier east side and are often the better choice during a west-side episode.
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.