40 µg/m³ measured at Great Falls, 1 km away, at Aug 06, 10:00AM. The NowCast smoke average is 39 µg/m³ — Unhealthy for Sensitive Groups on the US EPA scale.
Sensitive groups — children, seniors, and people with heart or lung conditions — should reduce prolonged outdoor exertion.
Forecasts show smoke increasing, peaking near 90 µg/m³ within the next 48 hours.
The current smoke should clear by about Aug 07, 10:00AM.
● Observed · ● FireSmoke · ● FireWork · ● HRRR
Background bands (US EPA AQI, 24-h basis): ■ Good · ■ Moderate · ■ Unhealthy for Sensitive Groups · ■ Unhealthy
| Model | Peak PM2.5 | Peak around |
|---|---|---|
| HRRR-Smoke (NOAA, 3 km) | 90 µg/m³ | Aug 06, 1:00PM |
| FireWork (ECCC) | 28 µg/m³ | Aug 07, 6:00AM |
| FireSmoke (UBC BlueSky) | 36 µg/m³ | Aug 06, 7:00PM |
Model values are for the ~10 km grid cell nearest Great Falls; the two models are independent and often disagree — treat the higher value as the cautious planning number.
Observations and NowCast are total PM2.5 — wildfire smoke plus every other source — as regulatory monitors measure it, and FireWork models that same total. FireSmoke is a smoke-dispersion model: it estimates the wildfire contribution only, so it reads lower than the monitors whenever other sources matter. The map's optional plume layer is likewise fires-only.
Smoke is at the surface and overhead.
● At the ground · ● Overhead (if mixed down)
Overhead smoke dims the sun but is not what you breathe. The dashed line shows the surface level if the whole column mixed through the boundary layer — a worst case, not a forecast · Data: NOAA HRRR-Smoke
Open the live chart for Great Falls — hourly observations, NowCast and both model forecasts.