Wildfires continue to ravage large tracts of forest in Canada, with little sign weather will provide much help to firefighters who are battling the blazes that sent smoke more than 1,000 miles southward and prompted air hazard alerts in cities on both sides of the US border.

More than 400 forest fires are still active across the country, and most of them are out of control. Prime Minister Justin Trudeau said Canada was living through its “worst wildfire season” in recorded history during a briefing with journalists in Ottawa on Wednesday.

Trudeau and President Joe Biden spoke about the fires …