Picture of downtown St. Paul from about 1 mile away, as rain falls and buildings are nearly obscured by thick ground smoke on June 3, 2025. Image credit Minnesota State Climatology Office.
Large wildfires in the Canadian forests of Manitoba and Saskatchewan produced heavy plumes of smoke that drifted over adjacent areas and got funneled into Minnesota on a series of wind shifts, beginning towards the end of May and lasting into June. Some of the smoke appeared to thicken as rain fell.
The smoke was generally densest in northern Minnesota, where for a period of several days beginning around May 28th, the fine particulates made it down to ground level periodically, causing poor air quality and driving some residents inside. On Monday June 2nd, the Minnesota Pollution Control Agency urged people in northwestern Minnesota to stay inside because concentrations of fine particulates reached the Maroon, or "Hazardous" (for everyone) category, the highest and most dangerous category on the national Air Quality Index.
In other parts of northern Minnesota, the Air Quality Index was Red (Unhealthy) for much of the time, or occasionally Purple ("Very Unhealthy"), and these conditions spread into central and southern Minnesota on Tuesday following the passage of a smoky cold front.
In the Twin Cities area and elsewhere in southern Minnesota, the smoke reached peak intensity as a steady rainfall event was occurring on Tuesday morning and early afternoon. Visibility dropped down to 1 to 2 miles, almost entirely because of smoke pollution, with some areas seeing visibility drop below one mile--similar to visibilities experienced during accumulating snowfall.
Beyond Minnesota's borders, even thicker smoke was observed in parts of North Dakota and Manitoba, much closer to the originating fires. Faint, milky skies from smoke particulates suspended high in the air made it down into the southern US, and most of the central part of the country observed at least some smoke during this period.
June 3, 2025
KAB