Smoke from raging wildfires in Canada has prompted air quality alerts across multiple states in the Midwest and Plains, leading to concerns about unhealthy air for millions. Thousands have evacuated as fast-moving fires continue to spread, resulting in hazy skies and orange shrouds over the eastern U.S. Cities like St. Louis and Cincinnati are experiencing significant pollution, prompting health departments to advise residents to stay indoors and monitor for respiratory issues. As winds carry the smoke southward, regions from South Dakota to the Carolinas are affected, with alerts extending through the weekend. The impact on visibility is notable, with some reports indicating that the Northern Lights in Minnesota may be obscured by the smoke.