32 µg/m³ measured at Butte, 3 km away, at Aug 06, 10:00AM. The NowCast smoke average is 27 µg/m³ — Moderate on the US EPA scale.
Unusually sensitive people should consider reducing prolonged outdoor exertion.
Forecasts show smoke increasing, peaking near 80 µg/m³ within the next 48 hours.
Smoke is expected to arrive around Aug 06, 12:00PM.
● Observed · ● FireSmoke · ● FireWork · ● HRRR
Background bands (US EPA AQI, 24-h basis): ■ Good · ■ Moderate · ■ Unhealthy for Sensitive Groups · ■ Unhealthy · ■ Very Unhealthy
| Model | Peak PM2.5 | Peak around |
|---|---|---|
| HRRR-Smoke (NOAA, 3 km) | 57 µg/m³ | Aug 06, 3:00PM |
| FireWork (ECCC) | 54 µg/m³ | Aug 07, 10:00AM |
| FireSmoke (UBC BlueSky) | 45 µg/m³ | Aug 07, 9:00AM |
Model values are for the ~10 km grid cell nearest Butte; 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 Butte — hourly observations, NowCast and both model forecasts.