Environment Canada has extended heat warnings to cover all but the western edge of British Columbia, and the sizzling conditions are also forecast for the entire northern half of Alberta and parts of Yukon and the Northwest Territories.
Temperatures into the 40s are expected for many parts of B.C., as the weather office says an exceptionally strong ridge of high pressure has parked over the province and likely won't budge until after Canada Day.
Many communities across the northern half of Alberta could also see temperatures near the 40 C mark by early next week.
Forecasters also warn most areas of Alberta and B.C. could see little reprieve from the heat at night as the mercury isn't expected to fall much below 20 C.
Environment Canada says sweltering conditions will extend to parts of southeastern Yukon by Saturday, where temperatures in the low 30s aren't expected to ease until next week.
It will be only a few degrees cooler in the Northwest Territories as heat warnings are posted from the Alberta boundary past the Arctic Circle, almost to the Beaufort Sea.
The weather office says heat warnings are issued when very high temperatures or humidity are expected to raise the risk of heat illnesses, such as heat stroke or heat exhaustion.
Those who are especially vulnerable include seniors, young children, those with chronic diseases or mental illness, the underhoused or homeless and anyone working outside.
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