This is Scientific Americans' 60-Second Science. I'm Emily Schwang.

A willess and speechless human believed to have died and been supernaturally reanimated.

A person markedly strange in appearance or behavior. A mixed drink made of several kinds of rum,

liquor and fruit juice. According to Miriam Webster, these are all ways to describe a zombie.

But maybe that definition should also include mention of wildfires, the kind that smolder

and creep along underground in the boreal forests of the far north and subarctic.

You know, we think they're out and, you know, there's snow and it's cold all winter.

And then in the spring, when they start smoking up again, it's like they're back from the dead.

This past spring, Randy Jant and her colleagues published a paper in Nature about wildfires

that overwinter in the boreal forest. Jant is a former wildland firefighter.

She's also a fieryologist at the University of Alaska Fairbanks, Alaska Fire Science Consortium.

If you were to ask me about that in the 90s or in the 80s when I started working in Alaska

and in the fire community, I would have said, gosh, that is just a really rare thing.

Jant can recall one memorable zombie fire which reignited after overwintering in May, 1996.

It stands out not only because of how much work it took to put out, but also because in 1996,

this kind of fire, one that overwinter was very rare.

But according to the study in Nature, zombie fires are becoming a more frequent phenomenon.

These can be stubborn, deep burning fires that require pumps and hoses and a lot of effort to put out.

One of our colleagues who had a full career smoke jumping in Alaska, 46 years as a wildland firefighter,

saw that article in Nature and related that it was an overwinter fire near Eagle, Alaska.

That was the most work per acre of any fire he was ever on in that 46 years.

I thought that was pretty remarkable.

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