Alaska Has Underground Zombie Fires That Smolder All Winter And Wake Up In Spring

Beneath the frozen surface of a northern wilderness, fires are quietly burning right now. Invisible.

Patient. Waiting for the snow to go away.

I first heard about this and honestly thought someone was pulling my leg. Underground fires that survive an entire Arctic winter and then crawl back to the surface in spring?

It sounds like bad science fiction. But zombie fires, as scientists actually call them, are completely real.

And they are spreading. Deep in peat soil and carbon-rich ground, flames smolder through months of darkness and snow, barely alive but never fully dead.

Then the melt comes. Oxygen rushes in.

And those sleeping embers wake up hungry. I have chased waterfalls, volcanoes, and glaciers across this planet.

Nothing prepared me for the idea of fire breathing beneath ice. This is one of the most fascinating and unsettling things happening in the natural world today.

It tells us something real about how fast our planet is changing. Some adventures are about beauty.

This one is about listening to a warning. Go north.

Watch the ground. And pay attention.

What Exactly Are Zombie Fires?

The name alone is enough to stop you mid-scroll. Zombie fires, officially called holdover or overwintering fires, are wildfires that do not fully extinguish when the cold season arrives.

Instead of dying out, they burrow downward into the peat soil and keep burning underground, sometimes for months at a time.

Peat is basically compressed, partially decomposed plant material that has been building up in Arctic soils for thousands of years. It is incredibly carbon-rich, which makes it excellent fuel.

Once it catches, it can smolder slowly at low temperatures without needing much oxygen at all.

These fires essentially hibernate through winter like a bear, except instead of waking up hungry and groggy, they wake up and set the landscape on fire again. Scientists have confirmed that the same fire can reignite in spring at or near the same location where it was burning the previous fall.

That behavior is what earned them the zombie label, and honestly, it fits perfectly.

How Peat Soil Turns Into the Perfect Underground Fuel

Peat bogs cover enormous stretches of Alaska, and most people drive past them without giving them a second thought. They look like soggy, spongy ground covered in moss, not exactly dramatic scenery.

But underneath that humble surface lies one of the most combustible substances on Earth.

Peat forms over centuries as dead plant matter accumulates in waterlogged areas faster than it can fully decompose. In some parts of Alaska, peat layers stretch several meters deep.

All of that organic material is essentially stored carbon, and when it burns, it releases massive amounts of greenhouse gases back into the atmosphere.

What makes peat especially dangerous as a fire fuel is its ability to sustain slow combustion without a flame. It does not need to blaze visibly to keep burning.

The smoldering process generates enough heat to keep itself going, and the insulating properties of frozen soil above can actually trap that heat in place through the winter months. By the time spring thaw arrives, the fire has been quietly working its way through the soil, ready to emerge again at the surface with very little warning.

The Role of Climate Change in Waking These Fires Up

Alaska is warming roughly four times faster than the global average, and that acceleration is directly connected to the rise of zombie fires. Warmer temperatures dry out peat soils that were once kept moist by permafrost and consistent precipitation.

Drier peat ignites more easily and burns more persistently.

Recent research suggests that rapid atmospheric warming can cause peat soils to heat up to smoldering temperatures entirely on their own, even without a surface fire to start the process. That means climate change is not just making existing fires worse.

It may actually be creating new ones from scratch through a kind of spontaneous underground combustion.

The feedback loop here is genuinely alarming. Zombie fires release carbon dioxide and methane as they burn through ancient peat deposits.

Those emissions contribute to more warming, which dries out more peat, which creates more fires. Scientists are watching this cycle with serious concern.

Over the past two decades, the frequency of these overwintering fires has increased significantly across the Arctic, and the trend shows no signs of reversing without major changes to global emissions patterns.

Spring Reignition and Why It Catches Everyone Off Guard

There is something deeply unsettling about a fire that disappears in October and then shows back up in May like it never left. Spring reignition events happen when the snow melts and the insulating layer above the smoldering peat is removed.

Suddenly, the underground fire has access to more oxygen and often drier surface conditions.

For fire management teams in Alaska, this creates a serious logistical headache. A fire that was considered contained or extinguished in the fall can reappear kilometers away from where crews last worked on it.

The underground spread is difficult to track, and the reignition point does not always match the original fire location.

I find it genuinely mind-bending that a fire can travel underground through the winter, moving slowly through peat in ways that leave no visible trace on the surface above. By the time smoke appears again in spring, the fire may have already established itself across a wide underground area.

Early detection tools including satellite thermal imaging are improving, but the challenge of monitoring something invisible beneath frozen ground remains one of the trickiest problems in wildfire science today.

The Carbon Bomb Hidden Beneath Alaska’s Surface

Alaska’s peatlands store an almost incomprehensible amount of carbon. Estimates suggest that Arctic and boreal peatlands hold roughly twice as much carbon as is currently in the entire atmosphere.

That carbon has been locked away for thousands of years, slowly accumulated by mosses and sedges in cold, wet conditions.

Zombie fires are essentially unlocking that storage one smoldering meter at a time. Each fire season, ancient carbon that took millennia to accumulate gets released in a matter of weeks or months.

The 2024 fire season in the broader Arctic region was particularly intense, with researchers documenting record levels of carbon emissions from peat fires across Canada and Alaska combined.

What makes this especially sobering is that the carbon released from deep peat layers is not new carbon cycling through the system. It is ancient carbon that was effectively removed from the atmosphere long ago.

Releasing it now adds to the total atmospheric load in a way that freshly burned surface vegetation does not. Scientists refer to this as legacy carbon loss, and it represents one of the most significant and least reversible consequences of Arctic warming currently being observed.

How Scientists Track Fires That Cannot Be Seen

Tracking a fire that burns underground with no visible flame is one of the more unusual challenges in environmental science. Researchers have developed a combination of tools to locate and monitor zombie fires, and the technology involved is genuinely impressive given the scale and remoteness of the terrain.

Satellite thermal imaging is the primary tool for large-scale detection. Sensors aboard satellites like NASA’s MODIS and VIIRS systems can detect heat anomalies at the surface even when no visible flame is present.

Ground teams then follow up on flagged areas to confirm active smoldering and assess the extent of underground burning.

Drones equipped with thermal cameras have become increasingly useful for closer inspection in areas that are difficult to reach on foot. Alaska’s terrain is notoriously rugged, and many of the most active peat fire zones are far from roads or infrastructure.

Some research teams also use soil temperature probes and gas sensors to detect the carbon monoxide and methane that smoldering peat releases. Combining all of these methods gives scientists a clearer picture, though the underground nature of these fires means there is still a significant margin of uncertainty in any given assessment.

What Zombie Fires Mean for Alaska’s Future

Alaska is not just a backdrop for zombie fire stories. It is the front line of a much larger transformation happening across the entire Arctic.

The fires burning underground right now are symptoms of an ecosystem under serious stress, and the consequences extend well beyond smoke and scorched ground.

Communities in rural Alaska, many of them Indigenous villages, deal with smoke-related air quality issues that stretch across entire seasons. Wildfire smoke contains particulate matter and toxic compounds that cause respiratory problems, and zombie fires that smolder for months contribute to prolonged exposure.

For people already living in remote areas with limited healthcare access, this is a real and immediate public health concern.

The ecological damage is also significant and long-lasting. Boreal forests and tundra ecosystems that burn repeatedly lose their capacity to recover at the same pace.

Permafrost thaws faster in burned areas, which leads to ground subsidence, altered drainage patterns, and further carbon release. Alaska’s landscape is literally changing shape because of these fires.

Understanding zombie fires is not just an academic exercise. It is part of figuring out how to protect one of the most ecologically important regions on the planet during a period of rapid and unpredictable change.