Fires expected to die down near Canada's oil sands, but summer fire season approaches

The threat of a Canadian wildfire near Fort McMurray, Alberta, appeared to be easing. Thousands of residents have already been forced to evacuate their homes.

But scientists have said it's not clear that wildfire smoke will be the same problem it was last year, when unusual weather patterns drove the haze southward.

In Fort McMurray, about 6,600 residents fled parts of the city's southern end while others were on alert. It was familiar terrain for the Albertan city, which survived a catastrophic blaze in 2016 that destroyed 2,400 homes and forced more than 80,000 people to flee.