Smoke, heat and 100+ burning wildfires force thousands to flee US wilderness; evacuations underway

More than 100 wildfires are burning in Canada, with smoke causing unhealthy air conditions from Minnesota through Toronto and into New York.

Boundary Waters Canoe Area Wilderness in Minnesota is closed due to about 17 lightning-caused fires; rangers estimate 6,000 to 10,000 people were inside the 1.1-million-acre wilderness.

Evacuations are underway primarily by canoe; rangers had about 90% of people out as of Wednesday, with no injuries or deaths reported.

Unusually hot summer temperatures are coinciding with the smoke, prompting health warnings to stay indoors.