The alert comes as humidity is expected to increase Tuesday, with high temperatures in the mid 80s to low 90s, with heat indices reaching 100 by Wednesday.

The Dragon Bravo Fire in Arizona has destroyed dozens of structures and a water treatment facility on the Grand Canyon's North Rim.

The Dragon Bravo Fire has destroyed dozens of structures and a water treatment facility on the Grand Canyon's North Rim.

A fast-moving wildfire near the Grand Canyon’s North Rim has destroyed the historic Grand Canyon Lodge and dozens of other ...

Wisconsin, Minnesota and Indiana all have air quality alerts, while Chicago's air quality currently ranks in the "unhealthy for sensitive groups" category.

Much of the Upper Midwest on Saturday was dealing with swaths of unhealthy air because of drifting smoke from Canadian wildfires, covering the northern region of the U.S. at a time when people want to ...

A massive wildfire near Arizona 's Grand Canyon National Park erupted overnight, growing more than 20 times in the past 24 ...

Canadian wildfire smoke returned to Wisconsin this weekend, with unhealthy levels for people with asthma and heart disease.

Most of Minnesota and parts of Montana, North Dakota and Wisconsin were ranked “unhealthy” for air quality on a U.S.

Wildfire smoke from Canada has made for bad air quality over parts of the Upper Midwest. Most of Minnesota had “unhealthy” ...

About 20 lawyers, support staff and U.S. Marshals who worked with Jack Smith were terminated, according to the sources.