World leaders may face smoke warnings when they gather next week in Alberta as wildfires burned out of control across much of Canada and caused the country's second-worst fire season in decades. The Kananaskis area of the Canadian Rocky Mountains,

Forecasters warn that hazy, grayish-blue skies could persist for many weeks as fires continue to burn, though most smoke will remain high in the atmosphere.

An air quality map shows conditions improving in the U.S. on Friday as smoke from the Canadian wildfires subsides.