Ruminations: You're Kidding! Zombie Fires?!

"All I know in Canada is that their existence has been reported more as a matter of folklore."
"And what this paper does is give us some idea how often these things might be happening."
Steven Cumming, associate professor, department of wood and forest sciences, Laval University

"In some areas, a fire can come back to life and start being a flaming fire again."
"So, the idea that because it can come back without a new ignition source burning and smouldering all winter, we call that a zombie fire. The term zombie fire is relatively new."
"Perhaps they are becoming more common, but perhaps we're also getting a little bit better at, well, hunting them down, to use the zombie terms."
"I would say we're not at a stage of what I would call a zombie fire apocalypse, to use another zombie term, but I think it's important because the scientists found that it was linked to hot summers."
James Waddington, professor, school of Earth, environment and society, McMaster University

A holdover or "zombie fire" from December, 2020 near Fort Smith, Northwest Territories is shown in a handout photo. (THE CANADIAN PRESS)

They were considered in the realm of urban myths, scare stories, improbable and mystical, someone's idea of a cautionary tale, but further research into the phenomenon appears to validate the presence of what has been named 'zombie fires', in Canada's far northern regions. Fire in forests thought to have been extinguished, but deep under the soil, with the right conditions, those fires continue to simmer, even though above ground winter has brought along deeply-piled layers of snow and the cold atmosphere of winter months.

They do occur, those zombie fires. They are a reality. And they are set in future, according to environmentalists, to become more common as the environment continues to warm, setting the stage for a perfect weather combinationm the presence of which becomes the perfect staging ground for below-surface smouldering remnants of a wildfire refusing to die, awaiting the opportunity to rekindle into yet another challenging wildfire.

According to professor Cumming, experts in fire management have long been familiar with the stories of underground blazes continuing to smoulder overwinter, but there were no records kept for the simple reason that there was no way to count them. And then along came a recent study, published in the science journal Nature, which claimed increasing summer temperatures associated with climate warming may promote overwintering fires' survival in boreal regions.

These fires are also known as holdover fires, mostly seen in the sub-Arctic, Arctic, Northwest Territories and the northern boreal forests in Ontario, Alberta and Saskatchewan, where peat moss can be found in vast quantities. The dreadful fire that almost destroyed Fort McMurray in Alberta and a few fires that occurred in the Northwest Territories fall into the category of zombie fires.

Fires that tend to burn deeper in organic or peat soils resulting from hot summers; are likelier to be detected the following spring, explained Professor Waddington. "And the more carbon you have, the more warming you have, the more waming you have, the more fire, so it's a cycle", pointed out Mike Flannigan, professor of wildland fire at the University of Alberta. Holdover fires emit a lot more carbon than normal forest fires, he also pointed out.

Peatlands, he explained, are carbon reservoirs built up over thousands of years. Burning one kilogram of peat emits roughly half a kilogram of carbon into the atmosphere.