Overview
- Smoke from roughly 850–900 active Canadian wildfires blanketed large parts of the U.S. Great Lakes, Midwest and Northeast on Thursday and continued into Friday, forcing widespread air‑quality alerts.
- Several major cities recorded very unhealthy to hazardous readings, with IQAir and monitors showing AQI spikes around 500–600 in places such as Detroit and Milwaukee and record hourly values in the Twin Cities.
- Local and state authorities issued stay‑indoors guidance, handed out N95/KN95 masks at transit hubs and closed outdoor venues and events after hospitals reported increased respiratory cases and some workers were hospitalized.
- Forecasters said a frontal passage should clear some smoke on Friday but warned northwesterly winds, shifting storms and recirculation could send new plumes back over the weekend, prolonging exposure for millions.
- The episode has renewed political pressure over cross‑border fire management and highlighted how climate-driven warmer, drier conditions are lengthening fire seasons and increasing long-range smoke risks.