What if I told you that this fire here burning right now wasn't caused by lightning or a campfire or even a cigarette butt no this fire started last summer and it spent almost all of this time simmering underground ever since right now in Canada there's a record number of these types of fires that went into hibernation all winter and are.
Coming back now with a Vengeance they call these zombie fires because of how they seem to come back from the dead but how's this possible how can a fire survive for many months under layers of wet snow and then just kind of spring back to life and why are we seeing so many of them now let's go through it last summer a group of massive.
Wildfires erupted here in the Rocky Mountains not far from the town of Fort Nelson but as winter rolled around and the Wildfire season fizzled out those fires never actually died they just moved underground let me explain it this way if you think of a campfire that naturally dies down after a few hours the flame might disappear but the Embers.
They're still smoldering right and for the next few hours that campfire is just kind of waiting for you to add another log or fan it extra hard so it can relight that's essentially what's happening here too except below the surface where it's very difficult to detect and if it's hot enough and and dry enough and last summer was the.
Hottest on record they can burn deep if you have water up close to the surface of the soils it's really hard for fire to burn very deeply when you have a lot of dry soil at the surface then those fires can can really kind of dig in and that depth is a big part of how these fires are able to survive so long because when a fire is that deep.
Underground the soil can actually start to insulate it and protect it from things like like snow and ice that firefighters are having to work harder than ever to really dig deep uh into those hot swats which are burning up to fourt deep in some places we've had reports of into the.
Soil now you might be thinking back to science class right now and wondering doesn't a fire need oxygen and some sort of fuel source to keep burning like it's pretty obvious how this version of the fire is surviving today it's got plenty of fresh air air and high wind for oxygen and a virtually endless supply of trees as fuel but just a few weeks ago.
When that same fire was underground where was the fuel and the oxygen coming from well the forest floor might look like it's solid but it's really not right like just think about when you water a plant those water molecules don't just sit on the surface of the soil the soil is is porous right so you have the water kind of creeping down.
Through these tiny spaces and air can do the same thing so you have these air pockets underground not very big ones mind you but you need surprisingly little oxygen to keep something smoldering and it turns out there's just enough oxygen to keep those Wildfire Embers alive they're able to stay burning deep in the soil underground uh.
With the little bit of oxygen that they do have okay so that's the oxygen what about the fuel if this soil was just full of sand or rocks these ground fires would die out eventually that's what happens most of the time California Australia Greece those places all have terrible Wildfire Seasons but none of them have this weird Undead horde of.
Zombie fires lurching out from underground coming back to life the only place we know of where this happens is here in the Boreal forest which stretches across Alaska Siberia and more than half of Canada this Forest produces the exact type of fuel these fires need to survive so long underground for one it's full of black Spruce one of the.
Most flammable trees on Earth all those pine needles and other dead plants they build up on the forest floor and because this area is so cold during the winter likeus 40° C isn't uncommon those plants decompose much slower than in most other places places creating a thick layer of soil full of partially dead highly flammable plants a perfect source of.
Underground fuel this is pretty different from other forests because they're biomass because they're made of a carbon this organic soil can can catch on fire and and burn through through the season and also um into the into the winter okay so now these zombie fires have made it through minus 40° weather.
They're all chanting brains as they get closer to the surface and they're so close to that warm dry weather they need to reemerge but they've got one last hurdle snow melt while the ground is Frozen all that snow packed on top of the soil helps insulate them but as soon as it starts to melt that water has got to go somewhere if you have a really.
Deep snow pack that leads to a lot of um moisture entering the soil and this can help to uh kind of quell those those over wintering fires normally the snow melt puts these underground fires out before they have a chance to turn into this but this year there were a couple things that got in the way first this was the warmest winter on record in.
Canada and it was a lot drier meaning there just wasn't a lot of snow to begin with so usually we' we'd see about 2 m of snow here 2 m so that's like taller than me yeah yeah exactly over our heads this year the snow in western Canada was you know between kind of 40 and 60% of normal and what little melt there was the soil was so dry it absorbed a lot of.
The water without allowing it to trickle down to those zombie fires when you have very dry ground subject to Drought uh then that moisture may not make it to all the places it would need to to completely extinguish all of these fires and so once these fires made it through winter all the way to Spring and once every layer above kind of had a CH to.
Warm up and dry up coming back to the surface is kind of the easiest part there's no shortage of plant life to burn along the way fires can climb route systems and they can sometimes even travel forwards underground until they reach fresh unburnt forest and then they work their way up above ground again from there the experts we spoke to said.
There's usually only a handful of these fires that managed to survive until the next Fire season but thanks to the perfect storm of bad conditions we've seen more recently there could be way more zombie fires this year we have had you know probably close to 200 over wintering fires that uh were identified um between British Columbia Alberta the.
Northwest Territories um there were there were a lot and so conditions are already right for burning and here's the thing those warmer than usual Summers and drier than usual Winters they'll likely continue scientists believe this part of the global North is warming up to four times faster than the rest of the world that means more fires more.
Zombies
