“Zombie fires” are forest fires that remain dormant underground during the winter and reemerge with the arrival of spring.
In the last decade, wildfires have worsened significantly due to climate change. Decreased soil moisture and dry vegetation act as fuel, facilitating the ignition and spread of fires in forests around the world. In countries such as the United States, Australia and Canada, increasingly intense and destructive fire seasons are being recorded, with millions of hectares burned and entire communities displaced.
As if this were not enough, the regions near the Arctic in Canada and the United States suffer from zombie fires. These fires remain active in deep layers of organic matter, such as peat, where there is enough fuel and oxygen to continue smoldering undetected.
In 2023, Canada experienced the worst wildfire season in its history, with more than 18 million hectares burned. This phenomenon did not end with the arrival of winter. In 2024, the number of zombie fires in Western Canada is 10 to 12 times higher than usual due to climate conditions such as a warmer, drier than average winter and reduced snow cover.
The danger of zombie fires
Zombie fires pose a significant risk because they can quickly reignite with the arrival of warm temperatures and spring winds. This extends the wildfire season, which normally begins in summer, into spring.
Currently, the Canadian provinces of British Columbia and Alberta are experiencing a resurgence of these fires, with numerous active outbreaks threatening to spread and cause more damage. Extreme drought and hot conditions increase this risk, and authorities have issued evacuation orders in affected areas such as Fort McMurray.
In addition to direct damage, zombie fires contribute to the release of greenhouse gases, exacerbating climate change. This vicious cycle makes wildfires more frequent and severe, creating conditions more conducive to future zombie fires.
To mitigate these risks, authorities are increasing their surveillance and prevention efforts, including hiring more firefighters and implementing bans on open fires near forested areas. However, fighting these fires is complex, as they require the removal of entire layers of soil to extinguish underground sources.
