Hundreds of sudden deaths, many of them suspected of being heat-related, have been reported during Canada's record-breaking heatwave, officials say.

Some 486 fatalities were recorded over the past five days in British Columbia alone, a 195% increase on the usual amount over that period.

Canadian Prime Minister Justin Trudeau offered condolences to families of the victims, many of whom were elderly.

Abnormally high temperatures have been recorded across North America.

British Columbia Chief Coroner Lisa Lapointe said on Wednesday: "It is believed likely that the significant increase in deaths reported is attributable to the extreme weather BC has experienced and continues to impact many parts of our province."

She said many of those who died in the heatwave had lived alone in homes that were not ventilated.

Ms Lapointe added that the western province had only seen three heat-related deaths over the past three to five years.

On Wednesday evening, the town of Lytton, British Columbia, was evacuated because of a wildfire - a day after it recorded Canada's highest ever temperature of 49.6C (121.3F).

Mayor Jan Polderman told CBC News: "The whole town is on fire. It took like a whole 15 minutes from the first sign of smoke to all of a sudden there being fire everywhere."

The heat over western parts of Canada and the US has been caused by a dome of static high-pressure hot air stretching from California to the Arctic territories. Temperatures have been easing in coastal areas but there is not much respite for inland regions.

The weather system is now moving eastwards over the Prairie provinces - Alberta and Saskatchewan and parts of Manitoba have been placed under Environment Canada heat warnings.

Janice Houldsworth, who lives in the British Columbia community of Castlegar, told the BBC she had not ventured outdoors for four days. "I've never experienced anything like this in all my 70 years," she said.

"We have blackened out all the windows, have fans running 24/7 constantly spraying with mist, cold foot baths, and showers and [are] drinking tons of liquid."

In Vancouver alone, heat is believed to have been a contributing factor in the deaths of 65 people since Friday.

At an affordable housing event in Kanata, Ontario, Mr Trudeau described heatwaves as a growing problem, and went on to talk about climate change.

Canada's southern neighbour, the United States, has also seen extreme heat.

In the US Pacific Northwest on Monday, temperatures hit 46.6C (116F) in Portland, Oregon, and 42.2C (108F) in Seattle, Washington, the highest levels since record-keeping began in the 1940s, the National Weather Service said.

In Oregon, authorities say at least 63 people have died from health issues related to the hot weather over the past few days. Forty-five of those deaths were recorded in Multnomah County.

At least 16 people have died in Washington state's King and Snohomish counties.

US President Joe Biden has also linked the heatwave to climate change in a speech.
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Can the heat be linked to climate change?
Analysis box by Matt McGrath, environment correspondent

I've heard from scientists who say that in just a few days they'll be able to determine just how much human driven warming has contributed to the searing temperatures seen in British Columbia.

One interesting piece of evidence is the lack of respite that night brings - recent temperatures at midnight in BC have been 2C warmer than the normal summer daytime figure.

Researchers say this combination of day and night-time heat is very dangerous for humans - a study published last year indicated that these compound events are closely linked to emissions of greenhouse gases.

Natural variability and local factors such as sea breezes can raise or limit the impacts of extreme heat. But the bigger picture is the rising thermometer of global heating is impacting all events.

"Every heatwave occurring today is made more likely and more intense by human-induced climate change," Dr Friederike Otto from the University of Oxford told the BBC.

"Climate change is definitely one of the drivers of the intensity of this Canadian heatwave - but it is not the only one and determining how much it impacts it, is a work in progress."

Even if they can't directly attribute this heatwave to climate change, experts say the fingerprints of global heating are all over it.

Risk of fire

Both Mr Trudeau and Mr Biden have warned of an increased chances of wildfires in the heatwave.

On Wednesday Mr Biden met with governors of western US states and fire officials, as the annual North American wildfire season began.

Jodi Hughes, weather presenter at Global News Calgary, told the BBC that firefighters were extremely concerned at the possibility of wild fires, possibly sparked by thunderstorms that could occur as the weather pattern changes.

Many homes in British Columbia do not have air conditioning as temperatures are usually far milder during the summer months.

One Vancouver resident told AFP news agency that hotels seemed to be sold out, as people flocked there for air conditioning, adding: "I've never seen anything like this. I hope it never becomes like this ever again."

Officials in British Columbia have warned residents against leaving their doors open, after a spate of bears wandering into people's home.

In Vancouver, residents have reported car windows cracking and melting, even when they are not parked in the sun.