Wildfires in the Arctic and boreal regions are increasingly becoming “zombie fires” — blazes that smoulder underground through winter and reignite in spring — causing long-term damage to forests and accelerating climate change.
A major example began in May 2023 in Donnie Creek, British Columbia, after a lightning strike ignited unusually dry forest. While the flames appeared to die out during winter, the fire continued burning slowly beneath the snow in organic, carbon-rich soil. It reignited in spring 2024 and ultimately destroyed more than 600,000 hectares of forest.
These fires burn deep in peat and permafrost soils, which store massive amounts of ancient carbon. Unlike fast-moving surface fires, zombie fires smoulder at lower temperatures for longer periods, releasing more greenhouse gases and harmful particles. Scientists warn this creates a dangerous feedback loop: warming dries the soil, fires burn deeper, and more carbon enters the atmosphere.
Beyond emissions, these fires severely damage ecosystems. They destroy seed banks in the soil, leaving behind mineral ground where forests struggle to regrow. Normal wildfires can help forests regenerate, but repeated deep burns prevent recovery.
Detecting zombie fires is difficult, so scientists are developing satellite-based monitoring systems. Similar activity is believed to be occurring in Siberia, though limited international cooperation has slowed research.
The problem is already affecting communities. In 2023, massive wildfires forced evacuations across Canada’s Northwest Territories. Scientists warn that as Arctic regions warm faster than the global average, these multi-year, underground fires are likely to become more common.
Researchers say winter, once a season of safety from fire, is no longer a reliable barrier.
