A 'heat dome' engulfing Canada and the US states of Washington and Oregon is thought to have caused dozens of deaths, officials said on Tuesday.

Police in British Columbia said they had responded to 65 sudden death callouts since the heatwave began in the region on Friday.

"Vancouver has never experienced heat like this, and sadly dozens of people are dying because of it," Sergeant Steve Addison of Vancouver Police said on Tuesday.

"Our officers are stretched thin, but we're still doing everything we can to keep people safe," he added.

Canada saw 103 heat records broken on Monday across the provinces of British Columbia, Alberta, Yukon and the Northwest Territories.

They included an all-time Canadian temperature high of 47.9C (118.2F) in Lytton, British Columbia.

The 'heat dome', which is the result of high pressure lingering over a particular area and trapping the heat, has also caused devastation across the border in the US.

Washington State and Oregon have both seen temperatures well above 40C (104F) since Friday.

People have been forced to sleep in 'cooling shelters', while others have experienced power cuts.

In Salem, Oregon on Sunday, the mercury rose to a record-breaking 44.4C (112F), while the National Weather Service recorded 42.2C (107.9F) in Spokane, Washington - another all-time high.

The heat is thought to have claimed at least six lives across the north west of the US, including a state nursery worker who was found unresponsive in a field and two homeless people in Oregon.

Commenting on the crisis in Canada, British Columbia's premier John Horgan said that it served as a "big lesson that the climate crisis is not a fiction".

"This is not a British Columbia problem, it's not a Canada problem, it is a global challenge," he said.

"And we all need to have citizens of the world coming together as we have, quite frankly, to address a global pandemic."