Canada Braces for Wildfire Season as ‘Zombie Fires’ Blaze

Canada’s emergency preparedness minister is warning that this year’s wildfire season will be worse than the record-breaking season of 2023, when thousands of fires burned tens of millions of acres and set off massive plumes of smoke that enveloped major U.S. cities, including New York and Washington.

This year’s fires could be especially bad in two of the country’s most fire-prone provinces, where nearly 150 of the blazes that started during last year’s season are still burning this winter, under snow-covered ground.

While so-called “zombie fires,” a term recently popularized in the Canadian media, are an annual phenomenon in parts of the country, never have so many fires been reported in a single winter, raising fears that many of them may flare up again above ground.

The “zombie fires” persist during winter because porous peat and moss ground cover in northern areas act as underground fuel for them.

The risk of wildfire in Canada has grown because of climate change, which increases the hot, dry and gusty conditions that have caused drought, according to research published last summer by World Weather Attribution, a group of scientists who model how climate change impacts extreme weather.

Given drought conditions in parts of Western Canada and other extreme weather effects, Harjit Sajjan, Canada’s emergency preparedness minister, said it was not surprising that the wildfire forecast was “alarming.”

He added that climate change “is the reality that we face and we need to get ready for it.”

Many of the underground fires — which are burning in the provinces of British Columbia and Alberta — don’t pose an increased risk of triggering wildfires in the spring because they are in places so charred that there is no vegetation left to burn.

But others are in areas that droughts have turned into tinder boxes, prompting fears that they will cause fires to erupt above ground once spring arrives.

Last year’s wildfires burned about 48 million acres of forest across Canada, an area roughly the size of Finland, and a staggering increase of 170 percent over the previous year, according to the Canadian Interagency Forest Fire Center.

Smoke from the fires, particularly blazes that burned in Quebec, wafted as far south as Florida and blanketed several cities in the United States and southern Canada in a noxious cloud.

The drought in Western Canada is now entering its third year and is a major factor behind fears of an even worse 2024 fire season, particularly in British Columbia and Alberta.

Both provinces have already seen new aboveground wildfires this year, prompting Alberta to declare a start to its wildfire season about a week before the traditional March 1 start date.

Snow could still fall in the spring and tame the existing fires and help with the dry conditions, said Mike Flannigan, a professor of wildfire science at Thompson Rivers University in Kamloops, British Columbia.

But this year, he added, long-range forecasts suggest continued dryness and warmer than usual temperatures.

About 93 fires left over from last year have continued to burn underground through the winter in British Columbia, while 55 are burning in Alberta, according to their provincial governments.

Such winter fires are common in both provinces, as well as in Yukon, but, in British Columbia, there are usually no more than about 15, experts said, adding that this year’s much higher tally has left them surprised and worried.

“There’s no historical analog to what we’re seeing right now,” Professor Flannigan said. “Most years they’re not a big deal. But now a lot of these fires have the potential that when the snow melts and it gets warm, dry and windy to actually grow again. So it is a serious issue.”

No overwinter fires have been recorded in the forests of Quebec, the eastern province that sent smoke billowing into the United States and at one point across the Atlantic Ocean to Europe. Quebec generally lacks the peat and moss soil of the western provinces that serve as fuel for winter fires.

Since the winter fires are underground and can produce little or no visible smoke, tracking them can be a challenge. The wildfire service for British Columbia said that it relied on sensors in airplanes and satellites to look for heat, though snow cover reduces their effectiveness.

Still, some fires have been visible to the naked eye.

“Even on the -40, -42 Celsius days, we were still seeing smoke,’’ said Sonja E.R. Leverkus, the senior fire lead at Northern Fire Worx, a private wildfire fighting service in a remote section of northeastern British Columbia. “So much that as you drove you’d be smelling the smoke and coughing in your truck.”

In a typical year, melting snow seeps into the ground where winter fires burn and snuffs most of them out. But this year there has been far less snow than usual, said Dr. Leverkus, who holds a doctorate in fire ecology.

“I am 6 foot 2, and there have been times in the past few years that snow on my apple orchard has been well above my hips,” she said, adding that there was less than foot on the ground.

Mr. Sajjan, the emergency preparedness minister, said that Canada was better prepared this year to fight fires and evacuate communities. While provinces and territories are responsible for fighting fires, federal money has provided for the training of an additional 600 firefighters across the country.

A system meant to allow provinces to share personnel and equipment has been revamped to make it more efficient and accelerate the exchange of information, Mr. Sajjan said.

Equipment stocks have been increased, he added, and new techniques and technologies — including nighttime firefighting — are being introduced or tested.

While the forecast for this year’s wildfire season seems dire, Professor Flannigan stressed that it was still only a prediction.

“I don’t expect to see another year like 2023 in my lifetime, but I could be wrong,” he said.

Still, he added, the long-term outlook for Canada was discouraging.

“Most every year is going to be a bad fire year,” Professor Flannigan said. “But on average, we’re going to see a lot more fire, a lot more smoke. This trend is going to continue.”

In Fort Nelson, British Columbia, Dr. Leverkus, whose crew numbers over 100 at the peak of fire season, said she was still haunted by the eight deaths among firefighters in Canada last year. Two of them occurred in areas near where her crews were working.

“Last year was horrible,” she said. “My crew and I, we listen to what the land is telling us. And the land is telling us that it’s dry, and the animals are telling us that it’s dry and to be ready.”

Vjosa Isai contributed research.