A heatwave has intensified over eastern parts of the United States and Canada, with Friday expected to be the hottest day yet.
Temperatures feel as high as 115F in places on the east coast, with no relief expected until after the weekend.
At least 22 deaths have been blamed on the heat.
Meteorologists attribute the temperatures to a ''dome'' of high pressure in the atmosphere.
The heat has also hit parts of Canada, with temperatures in Toronto expected to top 35C on Friday, according to Environment Canada.
The BBC reportsd that states more used to cold weather, including Minnesota and North Dakota, have been hit hard.
In the south, more than three-quarters of Texas is suffering from drought amid the worst dry spell in the state for decades.
Urban areas have opened cooling centres for the poor and elderly. The National Weather Service has warned people in normally cool areas to be especially cautious.