An air quality alert is in effect for the northern third of Minnesota through noon Sunday.
The Minnesota Pollution Control Agency reported that smoke from wildfires in Manitoba and Ontario has drifted across northern Minnesota.
"Air quality has rapidly deteriorated to unhealthy levels in many areas of northern Minnesota, reaching the Orange (unhealthy for sensitive groups) category," the MPCA reported in a news release. "Visibility has decreased to under 1-2 miles in many locations due to the dense smoke."
The air quality alert includes Duluth, Bemidji, Red Lake, Leech Lake, International Falls, the Iron Range and the Boundary Waters.
"The smoke is expected to move slowly southward over eastern Minnesota into Wisconsin today, tonight, and into tomorrow morning," the MPCA reported Saturday morning. "Air quality tomorrow morning will remain in the Orange category as a morning inversion further traps the smoke. Gradual relief is expected by tomorrow afternoon as northwest to west winds slowly move the smoke to the east out of most of Minnesota."
Officials said the smoke may cause problems for people with asthma and other lung conditions, and said all people in northern Minnesota may want to take precautions and limit physical activity while the smoke is in the air.