2024 wildfire season: Canada fights against "zombie fires" that survived underground from 2023

The persistence of "zombie fires" beneath the ground in Western Canada presents a formidable challenge for firefighters, especially considering the compounding factors of ongoing drought conditions and a lack of snowfall this winter, reportsPhys.org. 

Photo Credit: This handout picture provided by Alberta Wildfire from February 6, 2024 shows firefighters fighting an underground fire in Fox Lake that persists since last year,  despite the cold and snow. 

Last year, over 230,000 people were forced to flee their homes in Canada. The 2023 fire season in Canada was catastrophic for large parts of the North American continent, with smoke and reaching as far Florida. 2024 could be worse still. 

What are Zombie fires? 

As PBS wrote on February 23, Canada's 2023 wildfires never stopped, they just went underground as "zombie fires" smolder on through the winter. 

Despite being in the  middle of the winter 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 Canadian Interagency Fire Fire Center, CIFFC. Two of the of the fires the agency already classified as out of control.

These underground fires, fueled by dried peat and organic matter, can smolder for extended periods, remaining undetected until wisps of smoke emerge.

The situation is exacerbated by an exceptionally dry winter,  following a severely warm and dry summer, leaving Canadians preparing for another intense forest fire season. 

Eradicating these underground fires requires meticulous effort due to their hidden nature and slow-burning characteristics. Detection is challenging, and extinguishing them necessitates deep scraping of the ground to expose the burning humus layer.

The situation underscores the ongoing struggle to manage and mitigate the impacts of wildfires in the face of changing environmental conditions. As climate change continues to exacerbate drought and fuel fire conditions, proactive measures and increased resources are essential to protect communities and ecosystems from the devastating effects of wildfires.

The 2023 fire season in Canada was catastrophic for large parts of the North American continent, with smoke reaching as far Florida, and severely contaminating the air in major cities like Ottawa, Montreal and New York to often extremely unhealthy levels.  

"We are facing the most pressing challenges of our generation. Last year, over 230,000 people were forced to flee their homes in Canada"

Tweet from Harjit Sajjan, Emergency preparedness minister of Canada 

Fire Season 2024 could surpass that of 2023 in intensity

As NyTimes reported on March 5th, the warnings from Canada's emergency preparedness minister regarding the upcoming wildfire season paint a concerning picture, suggesting that it could surpass the severity of the record-breaking 2023 season. Last year's wildfires were already devastating, with thousands of fires burning tens of millions of acres and generating massive plumes of smoke that impacted major U.S. cities.

The persistence of nearly 150 fires from last year's season, still burning beneath the snow-covered ground, adds to the apprehension. These "zombie fires," as they've been termed, are an annual occurrence in some regions of Canada, but the unprecedented number reported this winter raises concerns about the potential for them to flare up again once they emerge above ground.

The situation is particularly alarming in provinces known for their susceptibility to wildfires, where conditions are ripe for the rekindling of these dormant blazes. The term "zombie fires" has gained popularity in Canadian media, drawing attention to the unique and concerning nature of this phenomenon.

The mild winter temperatures experienced this year, which were on average 4 degrees Celsius above seasonal norms according to the environment ministry, further exacerbate the situation. Warmer temperatures can accelerate snowmelt and drying of vegetation, creating conditions conducive to wildfire ignition and spread.

As Marc-Andre Parisien, a Canadian Forest Service researcher, points out, the combination of reduced snow cover and dry vegetation increases the susceptibility of forests, particularly coniferous trees, to ignition. 

Coniferous needles and leaves serve as highly flammable fuel, and even a small spark from lightning or other sources can ignite a fire under such conditions. The snow cover has decreased by 5 to 10 percent per decade since 1981.

Smoke despite temperatures 40 F / C below

On February 16, the BBC from Fort Nelson, BC, a small town in the north east of British Columbia. Sonja Leverkus, a firefighter and scientist who is local to the small north-eastern BC town, recalls the snowfall didn't look white when driving through a snowstorm in November 2023. 

"Rather", she said to the BBC, "it was blueish-grey because of the smoke in the air".

MS Leverkus is senior fire lead at Northern Fire Worx, which is a private wildfire fighting service in a remote part of northeastern British Columbia. 

To NYTimes, she said: 

“Even on the -40, -42 Celsius days, we were still seeing smoke, ... So much that as you drove you’d be smelling the smoke and coughing in your truck.”

Increased risk of wildfires lined to climate change

The link between climate change and the increased risk of wildfires in Canada is a well-established concern, as highlighted by research from World Weather Attribution and echoed by Canada's emergency preparedness minister, Harjit Sajjan. Climate change exacerbates conditions conducive to wildfires by creating hotter, drier, and gustier weather patterns that contribute to drought and the spread of wildfires.

Sajjan's acknowledgment of the alarming wildfire forecast underscores the urgent need to address the realities of climate change and its impacts. As temperatures rise and extreme weather events become more frequent and severe, it is crucial for governments and communities to prepare and adapt to the changing environment.

While the underground fires in provinces like British Columbia and Alberta may not directly pose an increased risk of triggering wildfires in the spring due to the lack of vegetation in charred areas, the broader context of climate change-induced drought and extreme weather underscores the ongoing threat of wildfires in Canada.

An area the size of Finland burnt

The staggering scale of last year's wildfires in Canada in 2023 differs somewhat depending on who is reporting. What is clear is that it is losses at a grand scale:

The BBC reports that more than 18 million hectares (44 million acres) of land were burned by wildfires in Canada in 202. That is reportedly an area roughly the size of Cambodia. This is far surpassing the country's 10-year average.

The NYTimes reports  a burned area of approximately 48 million acres of forest—an area roughly equivalent to the size of Finland—represents a significant escalation in wildfire activity, as reported by the Canadian Interagency Forest Fire Center. This marked a staggering 170 percent increase over the previous year, highlighting the severity of the situation.

Smoke creating unhealthy air conditions across the continent

The impact of these wildfires extended far beyond Canada's borders, with smoke from the blazes, particularly those in Quebec, reaching as far south as Florida and affecting numerous cities in the United States and southern Canada with a noxious haze.

The prolonged drought in Western Canada, now entering its third year, exacerbates concerns about the upcoming 2024 fire season. Particularly in British Columbia and Alberta, where new aboveground wildfires have already been reported this year, there are heightened fears of a potentially devastating fire season ahead.

The decision by Alberta to declare an early start to its wildfire season, preceding the traditional March 1 start date, underscores the urgency of the situation and the need for proactive measures to address the heightened risk of wildfires.