Residents have fled a small Canadian mountain village as wildfires raged during an unprecedented heatwave that triggered a large spike in sudden deaths.

At least 486 sudden deaths were recorded across the last five days in British Columbia, an increase of 195 per cent on normal levels, as Canada’s westernmost province wilted under record temperatures.

At 6pm on Wednesday evening, Lytton’s 250 inhabitants were told by the mayor, Jan Polderman, to evacuate to the nearby community of Boston Bar as flames tore through the village.

"It’s dire. The whole town is on fire," Mr Polderman told CBC News. "It took, like, a whole 15 minutes from the first sign of smoke to, all of a sudden, there being fire everywhere."

The wildfire season only just beginning, and officials fear that the extreme heat combined with a lack of rainfall could lead to widespread forest fires if the heatwave is followed, as expected, by thunderstorms.

Announcing the wave of sudden deaths, the province’s chief coroner Lisa Lapointe placed the blame directly on the heatwave and warned that the figure was only provisional and would likely rise in the coming days.

Justin Trudeau, the Canadian prime minister, told a press conference: “Our thoughts are with people who have lost loved ones”, and warned that it was a reminder of the need to address climate change.

British Columbia, which includes Canada’s pacific coast, normally experiences relatively mild summers with average high temperatures in Vancouver in June of just 22 Celsius (72 Fahrenheit). This week thermometers hit 46.6 Celsius.

In Lytton, located inland in a mountain valley, temperatures hit a Canadian record 49.6 Celsius, two degrees higher than the hottest temperature ever recorded in Las Vegas.

Such is the heat that, despite the region experiencing lower than average rainfall, rapidly melting snow and glaciers have cause British Columbia’s two major rivers, the Upper Fraser and the Chilcotin, to burst their banks. Flood warnings are in place across the province’s interior.

There have also been reports of buckled roads, melting power cables and car windows cracking across British Columbia and the US states of Oregon and Washington.

The heatwave, which was expected to move eastward towards the Prairie provinces yesterday, has been caused by a “heat dome” in which high-pressure air at altitude traps dense, hot air at ground level.

How a heat dome is formed

The heat dome is also bending the jet stream and preventing cooler weather from moving in.

Scientists are working to establish the extent to which this specific event can be attributed to climate change, but have said that global warming makes such events both more likely and more intense.