Canada’s 2024 wildfire season kicked into high gear with more than 120 wildfires in the drought-stricken British Columbia and Alberta regions this week, including some large out-of-control blazes that prompted evacuation orders in Alberta and conjured unwelcome memories of last year’s record-breaking wildfire season.

One of the more dangerous fires was reported near the city of Fort McMurray, where several neighborhoods were cautiously evacuated. On Tuesday, an evacuation order was issued for the Cold Lake First Nations community northeast of Edmonton. Three wildfires were considered out-of-control in the area, which is Canada’s largest producer of oil.

Another huge blaze dubbed the Burgess Creek Fire grew from 50 to over 1,600 hectares over the weekend and was up to 1,800 hectares by Wednesday. Local officials said this fire was most likely caused by human activity.

“Despite cloud cover and the cooler conditions there is still a high chance of any open flame escaping and growing. Just because it’s a bit cooler we still are seeing very dry conditions out there,” Cariboo Center Fire Information Officer Madison Dahl cautioned on Wednesday.

A local resident said on Sunday she could see “lots of trees going up like Roman candles” as the Burgess Creek fire exploded in size, putting much of the area under evacuation alert. The small town of Endako was completely evacuated after the winds shifted and the fast-moving blaze began spreading toward it.

CBC News quoted fire officials who said at least seven fires in British Columbia were believed to have been started by human activity, which could mean anything from an industrial mishap or carelessly-tended campfire to deliberate acts of arson.

Alberta imposed broad fire restrictions on Wednesday, urging “extreme caution” until drought conditions abate. In most parts of Alberta, all outdoor fires are now prohibited on public land.

“This is a critical time for wildfire in Alberta. Snow has melted and exposed dead and dry vegetation which is extremely flammable. Wildfires will easily ignite and can spread very quickly,” said Alberta Wildfire spokesperson Josee St-Onge.

Smoke billows from the Donnie Creek wildfire burning north of Fort St. John, British Columbia, Canada, Sunday, July 2, 2023. (Noah Berger/AP)

St-Onge was referring to the danger of “zombie fires,” an ancient phenomenon that only recently acquired its headline-grabbing appellation. Zombie fires continue smoldering throughout the winter, fueled by underground reserves of peat and moss, even though they have been buried under heavy layers of snow. Zombie fires can become active wildfires again once the snow melts.

According to St-Onge, over 200 fires have already been reported this year, compared to 135 at the same point in the record-setting year of 2023.

Smoke and air quality are major concerns during wildfire season, including in northern U.S. states that often feel the effects of Canadian wildfires. Minnesota Public Radio (MPR) on Thursday anticipated a rerun of the 2023 wildfire season, in which heavy smoke rolled south across the border and set some unwelcome records for poor air quality in Minnesota.

“It’s very concerning for us how we’re going to make out this summer,” Manitoba Wildfire Service acting director Earl Simmons told MPR, citing widespread accounts of zombie fires that might flare back into forest fires.

“The forest fires are getting more and more extreme. The fires are getting more and more volatile. It’s becoming more and more dangerous for firefighters,” Simmons said.

The American Lung Association’s 2024 State of the Air Report, released this week, found that soot particles from wildfires are the primary reason why 131 million people now live with unhealthy levels of air quality.

The association’s National Senior Director for Policy Katherine Pruitt told Forbes on Wednesday that wildfire pollution has become so severe that it is “reversing many of the air quality gains made through cleaning up industrial and transport emissions.”

“Wildfire smoke generates a lot of fine particle pollution, and because the heat of the wildfires is so intense, the plumes of smoke are being driven way up into the atmosphere and will spread over long distances,” Pruitt explained.