The first major heatwave of the summer is intensifying across the eastern half of North America, triggering health alerts and disrupting daily life for millions.
Heat warnings are in effect from the US Midwest to the East Coast, as well as in parts of Ontario, Quebec and Nova Scotia in Canada, impacting more than 160 million people through the week.
Experts warn that the soaring temperatures could aggravate the risk of heat-related illness, especially due to high humidity levels.
Compounding the danger is the extended duration of the event, with little nighttime relief - temperatures in some eastern cities may remain above 80F (27C) overnight.
The heatwave arrives less than a week after the official start of summer. Forecasters say several places may experience record highs.
