“Zombie” Fires in the Arctic— Clickbait or real?
Lately, you can read the term zombie fire in more and more media articles. A new way to gain views, or a real thing?
A guest blog post by Pierre Markuse
Zombie fires is a catchy name you can read in more and more articles and headlines in the media. With a reason, it attracts attention.
Now, before we begin to discuss whether zombie fire is a fitting name or more of an attraction-grabbing clickbait-naming we should take a look at what is usually described as a zombie fire.
What is it?
It all begins with an initial wildfire. Important in this case is that for it to become what is sometimes called a zombie fire it has to start in, or spread into an underground peat layer (or surface peat layer and be covered up by snow in winter). In these layers, the fire continues as smouldering combustion (Rein, 2013), without visible flames and, depending on the depth of the fire with lots of smoke visible or almost no visible smoke at all at the surface level. The fire then spreads, not only deeper into the ground, but also laterally following the pipe network within the peat layer, which allows enough oxygen to reach the fire and keep it alive. However, while there is enough oxygen to keep the fire alive, the fire will spread at a much lower speed underground or under snow cover, because the supply of oxygen is limited now. Depth-wise the fire is limited by the water table, laterally it could continue slowly burning through the complete peat layer. At times, following the pipe network, the smouldering fire can resurface and, given the right conditions, initiate a new flaming surface fire, even distant from the original starting point of the fire.
Acting like a zombie…
Since the fire might not be seen while burning underground the name zombie fire is being used by some to describe those fires. A fire starts, apparently dies, but then reappears, sometimes even distant from its original location. Just like a zombie coming back to “life”. This can happen days or even months after apparently dying down in the original location. This way fires can smoulder during the winter (hidden by a snow cover or in an underground peat layer) and then reappear on the surface months later, when the winter is over and conditions are more favourable for surface fires again.
Take a look at this illustration, explaining the spread of underground smouldering fires.
Zombie fire or no zombie fire?
Now that we know what we are talking about, is the name zombie fire fitting and can be used, or should it be avoided?
I asked the fire community on Twitter and this was the result.
As you can see 39% say it should be avoided. However, the majority believes the name to be either perfectly fine or while acknowledging its clickbait nature, find it suitable to use in this case.
Here are two opinions in favor of the name:
Attention is key
And while I’m not a big fan of the name zombie fire I have to agree. Getting science into mainstream media is hard enough. Zombie fire might sound laughable to some, but it garners attention and that initial attention might get people to read an article they otherwise would have not read, and that is always a win.
Those tweets are all from the same thread, you should read the whole discussion, also talking about another controversial moniker, the “megafire”.
But coming back to our zombie fire, what names are there?
Many names
Some would call it a holdover fire, which is correct but sounds a bit static, it seems to not include the spatial component, that a smouldering underground fire could extent laterally and pops up in a new surface location. I would say the same is true for the terms sleeper fire and the most-chosen overwintering (or over-wintering) fire. You could of course always just describe it as what's it is, a smouldering fire, however, not all smouldering fires are necessarily of the type that seems to disappear and reappear. Some of them burn, and sometimes quite visibly producing lots of smoke, through a peat landscape and that’s it.
In the end, everybody will use the name they are most familiar, and most in agreement with. Another reason why we should not expect the tern zombie fire to die out, as, for media, it will most certainly work best of all alternatives.
Why the sudden amount of zombie fire mentions in media?
Holdover fires are nothing new. Peatlands are known for them and landscapes within and around the Arctic Circle often have large areas of peat.
You might remember that last year the fire season within and around the Arctic Circle was a pretty active one. Just because of the number of fires we had last year, the chances for some of them turning into holdover fires in the peatlands in which they were burning is bigger than during a normal fire season. Add to that the warm winter and the recent heatwave in Siberia and you get the conditions for those holdover fires to reappear and keep on burning through the peatlands or initiate new flaming fires in the areas. This is why scientists believe that at least some of the fires we are seeing right now are holdover fires.
Take a look comparing the fire season in the Sakha Republic, Russia, this May to last year and the mean of 2003–2018. While it is too early in the fire season to make predictions, you can see that 2020 is for now on a good way to be an active season.
This image here, also showing 2019 and 2003–2018 data for the month of June makes clear why it is still a bit early to tell how things will develop, as usually most of the fires happen later in the year.
Why are Arctic wildfires dangerous?
While the temperatures on Earth are rising, wildfires within the Arctic Circle and regions just south of it are becoming more and more likely. This is dangerous because those fires often affect peatlands and not only add to the amount of carbon dioxide in the atmosphere (carbon dioxide which up until now has been stored in healthy peatlands) but peat fires also release methane, a far more potent greenhouse gas than carbon dioxide, accelerating the greenhouse effect, leading to rising temperatures and even more fires.
Depending on where in the Arctic, fires can be cause for another problem. Burn scars in the arctic can persist for quite some time before completely recovering, possibly changing the type of vegetation and facilitating the degradation of ice-rich permafrost (Jones et al., 2013), for example by decreasing the ground surface albedo, and therefore increasing the amount of energy absorbed, leading to higher surface temperatures. While frozen, the permafrost works as a storage for carbon monoxide and methane, but once thawing, it releases the stored greenhouse gases into the atmosphere, contributing to global warming.
Remote locations make it hard to battle fires
Another reason why fires in the Arctic are a problem is the fact that the Arctic regions are big and very remote. Even if detected, fire-fighting equipment is usually far away and often regions don’t even have streets. In Russia, many fires in Siberia will just burn until dying down naturally.
The problems with detecting holdover fires
Holdover fires are burning under snow cover and maybe even in underground peat layers. Directly detecting those fires using remote sensing satellites is almost impossible, the temperature differences at surface level are usually too small and localized for satellites to pick them up. However, at least some overwintering holdover fires can be classified using an algorithm for overwintering holdover detection. (Scholten and Veraverbeke, 2020) This allows us to classify a fire as overwintering holdover fire when it reappears, but it will still be invisible to remote sensing satellites until this happens.
Other methods of directly finding holdover fires (while still underground or snow cover) following bigger wildfires are more promising to find them, especially using infrared sensors with higher spatial resolution and sensitivity from planes and helicopters, as well as screening burn scars on foot using infrared sensors. Once located, it could then be possible to extinguish the fire, preventing it from reappearing again. Of course, these methods are more expensive and again hindered by the fact that a lot of Arctic wildfires are in remote locations.
Using the Sentinel Hub EO Browser to find and image wildfires
If you are interested in finding and imaging wildfires yourself, I recommend using the Sentinel Hub EO Browser. Its presets allow for quick results, and once accustomed to it, you can use custom scripting for even better results.
Should you be completely new to the EO Browser, reading “Remote Sensing in the Classroom — Getting Started Guide” will help you get started. While meant to get teachers to use it in the classroom, it lists a lot of resources that will help you to get going with your own images and scripts.
If you already know your way around the EO Browser, reading “Looking at Wildfires (and more…) — An Introduction” and “Visualizing Wildfires and Burn Scars with the Sentinel Hub EO Browser V2” might help you to specifically image wildfires using the EO Browser.
References
Jones, Benjamin M., Amy L. Breen, Benjamin V. Gaglioti, Daniel H. Mann, Adrian V. Rocha, Guido Grosse, Christopher D. Arp, Michael L. Kunz, and Donald A. Walker. “Identification of Unrecognized Tundra Fire Events on the North Slope of Alaska.” Journal of Geophysical Research: Biogeosciences 118, no. 3 (September 24, 2013): 1334–44.
https://doi.org/10.1002/jgrg.20113.
Rein, Guillermo. “Smouldering Fires and Natural Fuels.” Edited by C. M. Belcher. Fire Phenomena and the Earth System, September 2013, 15–34. John Wiley & Sons, Ltd, 2013.
https://doi.org/10.1002/9781118529539.ch2.
Rein, Guillermo and E. Burns. “Illustration of a smouldering peat fire initiated by flames in the surface” from “Smouldering Fires and Natural Fuels.” Edited by C. M. Belcher. Fire Phenomena and the Earth System, September 2013, 15–34. John Wiley & Sons, Ltd, 2013. https://doi.org/10.1002/9781118529539.ch2.
Scholten, Rebecca, and Sander Veraverbeke. “Spatiotemporal Patterns of Overwintering Fire in Alaska.” Fire Science Highlights Blog. Alaska Fire Science Consortium, April 8, 2020. https://akfireconsortium.wordpress.com/2020/03/25/spatiotemporal-patterns-of-overwintering-fire-in-alaska/.
I would like to thank Guillermo Rein and Mark Parrington for their help, as well as all people who contributed to my Twitter poll regarding the zombie fire name.
Pierre Markuse
Pierre Markuse is a freelance remote sensing expert and blogger with a special interest in optical remote sensing, his images being used by numerous media outlets.
How to make satellite images more approachable to the general public, communicating scientific backgrounds, and the usage of satellite images in journalism are additional fields of interest.
You can read more of his work on his personal blog here or take a look at his satellite images here on Flickr.
