Wildfires in Canada's oil city of Fort McMurray this year caused CAN $3.58 billion ($2.75 billion USD) in damages, making it the country's costliest disaster ever, according to estimates from insurers on Thursday.

The inferno swept through the Alberta city in May, dislocating about 100,000 people and laying waste to hundreds of thousands of hectares (more than a million acres), including thousands of homes and businesses.

"This wildfire, and the damage it caused, is more alarming evidence that extreme weather events have increased in both frequency and severity in Canada," said Don Forgeron, president of the Insurance Bureau of Canada (IBC).

It said the cost of the damage was more than twice that of the previous record-holder, the 2013 southern Alberta flood, which totaled CAN $1.7 billion in insurance claims.

Canadian insurers received more than 27,000 claims for personal belongings, more than 12,000 for vehicles, and more than 5,000 claims involving businesses, the insurance bureau said.

Those forced to leave Fort McMurray in May were allowed back home in early June but the authorities warned that the process of rebuilding would take a long time.

The Alberta provincial authorities lifted a state of emergency imposed because of the fire only this week, and declared the fire under control.

Nearly 6,000 square kilometers (1.5 million acres) of forest were charred and some 2,400 buildings were either destroyed or damaged by the flames.