Environment
Fire detection, forecasting, management — and how decisions are made
The May/June Canadian Geographic infographic looks at how we fight wildfires in Canada. We talked with wildfire expert Mike Flannigan on how fires on the landscape are managed — and what our future might look like. Read an extended Q&A below:
On who manages fires
It varies from jurisdiction to jurisdiction. Fire management is the responsibility of the landowner. So in this case, the 10 provinces, two territories. Nunavut has forests and fire, but they don’t have any fire management agency. Parks Canada [is another landowner]. So there’s a lot and each one does their own thing. So there are some general common features, but specifics vary from place to place. Some agencies allow fire to burn more or less naturally.
On how fires are detected
Today many fires are detected by the public, cell phones, people see a fire and they call it in. In most jurisdictions, that’s how the first detection happens. Some places, like Alberta, have lookout towers. Fires are also reported by aircraft, whether they’re fire management agencies or Air Canada, West Jet — they report fires when they see them as well.
On decision-making by fire management agencies
So once the fire’s reported, what they do in Ontario is they look at the fire and if it’s close to a town, it takes half a second to say that’s an unwanted fire and we’re going to send crews to put it out. If it’s not close to a community, they have a fire weather forecast for 15 days. They run a fire growth model to determine, “where will that fire spread if we don’t put it out?” And then they say, is this beneficial to the landscape or detrimental? And you’d say, “woah, woah, woah… fire is beneficial?” Absolutely. Fire is a natural part of our boreal forest, almost all our forest. It kills insects, disease. It’s the cycle of life. Many fire management agencies are trying to allow fire on the landscape when and where possible. As well as being natural, recently burned areas are unlikely to re-burn for 15, 20 years or longer. And if they do burn they’re often at lower intensity, and easier for fire management to put out.
If it looks like that fire is going to be beneficial or at least not causing any harm, they’ll say, “Okay, we’re going to watch it”. Then, the next day, they get a new fire weather forecast, run a new fire growth model and then do the assessment again. And so that’s how they handle those and they’re called “BOBs” — being observed. I think that is a great policy.
They like to make the determination within three minutes, because under extreme conditions we have maybe 15 minutes to take action. In less extreme conditions, you have probably half an hour to an hour, something like that. But, once you make the call the crews have to get to the helicopters. The helicopters physically have to fly there. It all takes time. So that’s why that decision making is so compressed. It has to be done really quickly. And as I said, some of them are really simple. A fire is just outside of Bancroft, you know, it’s a half second decision, done. You still run the fire growth model, do the fire weather forecast, but you’re already sending crews to it.
On fire forecasting
Just like weather forecasts, with fires it’s the exact same thing except we use a fire danger rating system: it’s called the Canadian Forest Fire Danger Rating System. And using the weather, it tells you how dry the fuels are. Then we have models that predict fire behavior based on how dry those fuels are and what kind of fuel it is. Conifers burn much more readily than broadleaf trees — so oaks and maples, their crowns don’t catch on fire as there’s too much moisture in the leaves. Whereas black spruce, pines, firs — they all burn very nicely. So we have all these models that tell you how fast that fire will spread based on this fire weather forecast, and how intense that fire will be.
These work pretty well actually, for the short term, just like the weather forecast. You know, today’s forecast is generally pretty good; forecast for next week, eh, not quite as good; forecast for two weeks away: who knows? There’s a lot of uncertainty as you move farther in the forecast window, but short term forecasts are pretty good. So they have a pretty good idea of where that fire is going to spread and how intense it will be. And then they look at the landscape and ask, are there any “values” on the landscape? Such as communities, mines, power lines, you name it.
On fighting unwanted fires
If the fire’s accessible by land, they send crews by truck. If it’s only accessible by air, then they helicopter the crews in and there’s different sizes of crews all across the country. This is called “initial attack.” You hit it hard; you hit it fast. If the fire’s the size of my office, it’s easy to put out. If the fire gets to the size of a football field or a soccer pitch, and it’s hot, dry and windy and the fuels are dry, now you have a serious problem.
If the fire is really hot, big flames, “high intensity” we call them. And we use this term “crown fires,” which means the fire’s spread from the forest floor up into the crowns of the trees, the tops of the trees. Crown fires are very intense fires, and you don’t want people in front of that because it’s too dangerous. So that’s usually the head of the fire, the direction the wind’s blowing, but usually on the sides of the fires, which we call the flanks, and the back of the fire, it’s much lower intensity. So it’s safe. And for firefighters, on foot, they carry — a lot of places like Ontario there’s lots of lakes — so they carry pumps and hoses. And they use water as much as possible. They also use shovels. Alberta is really big on bulldozers — they just bring a bulldozer in to dig a line around the fire … it’s quite effective. And of course, there’s aerial attack: helicopters, water bombers — they drop retardant mostly, but sometimes water, sometimes foam — with a “bird dog” plane flying in front to direct where to drop fuel.
The trick becomes in extreme conditions, you have a window of 15 minutes to put that fire out. Otherwise it’s like spitting on a campfire because it’s just too intense and too large. So you’ve got this narrow little window. That’s why detection and getting resources to the fire is so critical.
On using back burns as a firefighting tool
There is one other tool that is quite effective and that’s called back burning. It’s a fairly straightforward principle. So, the fire is spreading with the wind. If it’s a west wind the wind is coming from the west, blowing to the east, so the fire is spreading to the east. If you get in front of that fire and light a new fire, it’s spreading against the wind, so it’s much lower intensity. When the wildfire meets the back burn, the wildfire has no fuel because the lower intensity fire has chewed up all that fuel. It’s a very effective tool and they use it all the time.
However, there are a few issues. One is if the winds shift, you have a bigger problem than you had with just one fire: now you’ve got two fires. Another issue is that really intense fires have these burning embers … If you’ve seen video of the Fort McMurray fire, there was this rain of burning embers. Some of these little burning embers can be carried by the wind two kilometers. The Fort McMurray fire, for example, crossed the Athabasca River three times. And that was either 800 meters to 1,100 meters. It just jumped across. So if it’s a really intense fire, it could jump over your backburn into fresh new fuel and just carry on — so you wasted your time! Most breaches into communities, it’s not by direct flame — it’s by these rain of burning embers landing on mulch or on conifer shrubbery around your house or wood shingles or yellow pine needles in your eavestrough. Fire is opportunistic. It’s just probing, looking for a place to catch fire.
On evacuation as a last resort
I’m a big fan of, if possible, not evacuating. Evacuation is very traumatic. I’m thinking we should be building fireproof shelters in certain areas of the community so people can go there with proper filtration — obviously built out of brick or something, a non-flammable material — rather than evacuating the community. But sometimes evacuation is the only recourse because we don’t have these fire shelters in most communities. So evacuation takes place, and a lot of these are remote areas with Indigenous communities — they have to be flown out. Often the military gets called in to assist and sometimes people are away for months … but sometimes it’s necessary.
On the future of Canadian wildfires
Not every year is going to be bad. Last year was a really quiet year in Canada, one of the quietest years we’ve had for a while, but meanwhile, California had a crazy year. But on average, we’re going to see more fire. The key driver here is temperature. And people say, “woah woah woah, well, why is temperature so important?” And here I’m not talking about just one fire like Fort McMurray. And that’s where wind becomes really important. But I’m talking about fire over a larger area like Ontario, over a longer term, a month or a fire season.
Temperature is important for three reasons. One: longer fire seasons. Two: more lightning — reports suggest as we warm, there’ll be a 10 percent increase in lightning activity for every degree of warming. Now we have a fairly short lightning season in Canada. But if it gets longer and longer, we expect more lightning. And last, which is probably the most complicated, is the atmosphere’s ability to suck moisture out of the fuel, to dry the fuel, increases almost exponentially as we warm, unless there’s increases in precipitation to compensate for this drying effect. And the models for the future don’t suggest we’ll see enough precipitation increases to compensate. So the bottom line is drier fuels — drier fuels really drives the fire business because fuel dryness determines whether fire will start, whether it will spread and how much fuel is available to burn. Which means intense for that fire to be. If it’s too intense, these crown fires, then once they’re started, there’s not much we can do except for back burns and get out of the way.
So you see the fire start to spread, with more intense fires, more escaped fires, more difficult, challenging fires. That’s our future. And, you know, various agencies have had policies to try and suppress, extinguish all fire. It hasn’t worked. Our area burned has doubled since the 70’s. And it’s going to continue to increase as we continue to warm. So we have to learn to live with fire and smoke.
On how causes of wildfire are shifting
In Canada, roughly 50 per cent of the fires are started by lightning and 50 per cent by people. But the lightning fires are responsible for 80 to 90 per cent of the area burned. If you think about it, it makes sense because human caused fires are close to people, they’re reported right away — and because they’re close to people, they’re usually unwanted fires and put out right away. If you look at how our area burned has doubled — it’s due to lightning caused fires. Our area burned due to lightning caused fires is increasing. Our area burned due to human caused fires is decreasing. There’s many reasons why that may be: education programs, people putting out their campfires appropriately, fire bans, forest closures, sometimes. Fire bans work. And when things get really extreme, places like Ontario shut down commercial operations; logging operations can’t work if there’s extreme fire danger. So there’s no one in the forest. Because if you think about it, every human-caused fire is preventable.
We can’t do much about lightning-caused fires directly. We can do things about climate change by getting our act together as a global community and reducing greenhouse gases. But in the short term and the day-to-day weather and day-to-day lightning: now that’s beyond our current control.
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