Canada’s 2023 wildfire season was the most destructive ever recorded, with 6,551 fires scorching nearly 71,000 square miles of land from the West Coast to the Atlantic provinces, according to the Canadian Interagency Forest Fire Center. It wasn’t just remarkable for its destruction, however, but also for the fact that it never really seemed to end.

It’s the middle of the winter, and there are still 149 active wildfires burning across Canada, including 92 in British Columbia, 56 in the western province of Alberta, and one in New Brunswick, according to the CIFFC, which classifies two of the blazes as out of control.

“Zombie fires,” also called overwintering fires, burn slowly below the surface during the cold months. Experts say zombie fires have become more common as climate change warms the atmosphere, and they are currently smoldering at an alarming rate in both British Columbia and Alberta.

“I’ve never experienced a snowstorm that smelled like smoke,” Sonja Leverkus, a wildlands firefighter and ecosystem scientist based in British Columbia, told CBS News partner network BBC News.

“A lot of people talk about fire season and the end of the fire season,” she told Canadian public broadcaster CBC, referring to the period generally thought of as being from May to September, “but our fires did not stop burning in 2023. Our fires dug underground, and have been burning pretty much all winter.”

With the fires already burning, and unseasonably warm temperatures and reduced precipitation increasing the threat of more blazes, Canada’s western province of Alberta has declared an earlier start to its wildfire season.

The announcement prompted local authorities to allocate additional funding and other resources to help mitigate human-caused fires in designated Forest Protection Areas, according to a statement released this week by the provincial government.

“Alberta’s government will face the coming wildfire season head on, and we will do whatever is necessary to help Albertans and their communities stay safe from the impacts of wildfire. I want to encourage Albertans to remain vigilant and recreate responsibly,” said Todd Loewen, Minister of Forestry and Parks.

Smoke caused by the fires burning in the eastern Quebec and Ontario provinces sent a haze across the border into New York and several other U.S. states last year, worsening air quality and causing issues for people sensitive to pollution.

Authorities are already bracing for this year’s wildfires to be more intense as climate change brings even more extreme weather. 

In British Columbia, officials have already started upgrading and expanding the province’s firefighting aviation and ground fleets and sourcing more equipment.

“As we head into the spring and summer months, we are reminded of last year’s devastating wildfires and the impact they had on people and communities around the province,” said Bruce Ralston, Minister of Forests, in a statement. “The impacts of climate change are arriving faster than predicted, and alongside the task force, we are supporting the wildland firefighters who work tirelessly to protect us under the most extreme conditions.”

In a social media post on Wednesday, Canada’s national Minister for Emergency Preparedness Harjit Sajjan said extreme weather events forced more than 230,000 to flee their homes across Canada during 2023, calling climate change “the challenge of our times.”