Humans are the leading cause of wildfires in Canada, says a forest fire researcher who believes the latest blaze that has ripped through parts of Fort McMurray, Alta., is no exception.

Mike Flanagan, a professor of wildland fires at the University of Alberta, says the fire's proximity to the city, as well as data that shows there were no lightning strikes in the area, lead him to believe the cause of the fire was likely human.

"And in spring it's heavily loaded on the side of people-caused fires,'' Flanagan said.

50 per cent of fires caused by people

An average of 1,200 wildfires are reported in Alberta each year, and half of those fires are caused by humans, according to the National Fire Database. Lightning is the second-leading cause with 47 per cent.

Officials were still investigating the cause of the latest fire, which remained out of control on Wednesday as it raged around Fort McMurray, a city of about 80,000 people located 435 kilometres northeast of Edmonton.

However, Flanagan said weather conditions in Western Canada have been perfect for wildfires as the warm, dry winter has led to an abundance of dead, dry leaves and wood ready to light up.

"It's really extreme conditions,'' he said, adding that the low humidity and lack of green vegetation combined with windy conditions contributed to the incredibly intense fire in the northern Alberta city.