The roughly 1000 residents of Lytton had to abandon their homes with just a few minutes notice on Wednesday evening after enduring temperatures of 49.6C the previous day.

The province's public safety minister, Mike Farnworth, said on Thursday afternoon that most homes and buildings in Lytton had been destroyed and some residents were unaccounted for.

The British Columbia Wildfire Service said the Lytton blaze was raging out of control over an area spanning about 80 square kilometres.

Several other fires were burning in the region as a heatwave baked western Canada.

Lytton city council member Lilliane Graie, on behalf of mayor Jan Polderman, said in an email that the fire had devastated the town, which is a First Nations community about 150 kilometres northeast of Vancouver.

"Our people are scattered north and south and we are trying to establish who is where," she wrote.

At least some of the people who fled Lytton went to a recreational centre in Lillooet, a town about 100 kilometres to the north.

In a television appearance, British Columbia premier John Horgan said: "Three consecutive days of the highest recorded temperature in Canadian history all happened in Lytton this week. To have a heatwave and a horrific fire is so troubling and so challenging for the people of this community."

The heat in Lytton set its first national record on Sunday, reaching 45.1C, then set another high Monday, at 47.9C. After yet another record high on Tuesday, the heat eased to 39C on Wednesday.

Australian Associated Press