The National Weather Service said the alert will be in effect until Sunday morning in the Santa Clarita Valley and Saturday night in parts of Los Angeles, Ventura, San Bernardino, and Riverside counties.

For most of the past decade, forecasters have been able to use satellites to track these smoke plumes, but the view was only two-dimensional

The red alert, issued by the Minnesota Pollution Control Agency, means that the air quality is unhealthy for everyone. It will begin at 9 a.m. Sunday and last until 9 a.m. Tuesday, Aug. 12, for large portions of the state, including the Minneapolis-St. Paul area.