They say Muskoka won't burn. But climate has changed the calculus

Hamilton Spectator

23-06-2025

They say Muskoka won't burn.
The complex computer models that analyze fuel load in the forest and project wind, temperature and humidity say it is impossible.
But over the past few years, forest fires have started to do things no one thought were possible.
In 2018,
the town of Paradise, Calif.
, was engulfed in flames after a wildfire jumped a 500-metre-wide canyon that models had considered an unbreachable firebreak.
To witness how Ontario's Fire Rangers prepare to tackle wildfires, the Star headed to West Nipissing, near Temagami, as a prescribed burn at Sinton Creek was carried out.
The same state's Dixie Fire in 2021
sent flying embers 16 kilometres ahead of the main blaze, starting new fires farther away than any model considered feasible.
The Jasper, Alta., wildfire
last summer advanced eight kilometres in only four hours, fuelled by 100 km/h winds called 'unimaginable' by Parks Canada, 'driving the flames beyond any possible predictions.'
A forest fire risk map for the Muskoka Region, where red shows higher risk and yellow lower risk areas. A 2009 analysis found the region — broken up by roads, cottages and Ontario's signature lakes — was a relatively low risk for wildfires.
In 2009, the Western University-based Institute for Catastrophic Loss Reduction asked a researcher to
push the wildfire model as far as it would go
to see what conditions would be needed for Muskoka to go up in flames.
The response: it can't happen. Muskoka has too many big lakes, which cut up the forest and prevent a fire from growing too big, while the winds aren't strong enough to carry embers across them.
'He couldn't do it. No matter how absurdly hard he pushed the model, it just wouldn't go,' said Glenn McGillivray, managing director of the institute and a professor of emergency disaster management at York University.
But having seen wildfires repeatedly do things they weren't supposed to be able to do, McGillivray isn't so sure anymore.
'In all those cases, the models didn't allow it. But it happened,' he said.
Fifteen years ago, it was an accepted truth that Southern Ontario was safe from forest fires. We're now not so sure.
Supercharged by climate change
, wildfires are getting
bigger, hotter and harder to put out
. The number and size of forest fires are breaking records virtually every year, making historical data increasingly irrelevant.
In 2023
, more than 15 million hectares of forest burned across Canada — an area larger than the Maritime provinces — more than double the previous record and six times more than an average season. Nearly a quarter of a million people were forced to flee their homes for safety.
Wildfire season is starting earlier and ending later, if it even ends at all. Reports of
fire
s burning through the winter
— once considered an impossibility — are becoming more frequent, especially in B.C. where they can smoulder in the ground, under the snow, and emerge when warmer, drier weather returns.
'It's insane what's happening,' said Sudbury Fire Ranger Crew Leader James Paluch. 'We were fighting fires in November last year — big ones. That never happens. Out west, fires are kicking up that have been dormant for two years.'
This spring, the wildfire season has been fierce — and it's only just begun.
More than 1,900 wildfires have broken out, burning an area larger than 3.5 million hectares. States of emergency have already been declared in Saskatchewan and Manitoba, where more than 40,000 people have been evacuated from their homes as flames encroach.
Two people were killed
in May while attempting to flee a wildfire in Lac du Bonnet, near Winnipeg.
Speaking earlier this month, Manitoba Premier Wab Kinew laid out the stakes for Canadians: 'As a nation, we're going to have to contend with future fire seasons being more and more like this, which means scaling up our firefighting capability.'
Ontario, for the time being, has escaped relatively unscathed. The destruction wrought by wildfires has been concentrated in the West. But Ontario's vast boreal forest has all the characteristics needed to produce a monster wildfire, one that could sweep out of the forest and into a community this summer.
Videos of the iconic yellow-and-red Canadian waterbombers have coursed through social media as
With previously inconceivable fires now happening every year, it's important to understand just how many more places are at risk, said John Vaillant, the author of '
Fire Weather
,' a Pulitzer Prize finalist book that looked at the way climate change has fundamentally changed the characteristics of wildfires.
'We have to believe that Toronto can burn like L.A. We have to wrap our minds around that possibility,' he said. 'It's scary. It's sad. It totally undermines our sense of confidence in the future. And that's what climate change is really challenging us with. We really have to revise all that and it's really painful and difficult.'
Ontario fire rangers carry out a prescribed burn a typical Ontario forest in West Nipissing.
Officially, the populated areas of Ontario are low risk for forest fires. Most fires that break out each summer are concentrated in the remote northwest of the province. But close calls, where
fires were held back at the doorstep of population centres like Timmins
, aren't uncommon, and the risk of a fire breaking through into a city or town — or even cottage country — is widely ignored by folks in the south.
'The idea of Muskoka disappearing in a conflagration … you just don't want to go there,' said Vaillant. 'You could totally lose the whole thing. All you would need is a heat dome and a wind and a fire. But all that is totally possible. These are not unlikely events.'
The Muskoka Lakes Fire Department has not seen any wildfires escape containment, but is acutely aware of the risk, said local Fire Prevention Officer Douglas Holland.
'We've had a few fires get into the bush, but we've been able to stop them there,' he told the Star. 'We're lucky. Because we have such a mix of trees, a lot of our fires haven't gotten up into the canopy. They've stayed on the ground.'
'But that's not to say this isn't going to change in the future.'
The Muskoka fire department is conscious of the fact that climate change brings the risk of bigger wildfires and has placed an emphasis on communicating FireSmart practices to residents. This involves everything from clearing bush around homes to installing metal roofs to prevent house fires escaping into the bush and bush fires igniting homes. And so far, this has worked.
But the researcher who deemed Muskoka safe back in 2009 now says climate has changed his calculus.
'If you get a good solid, dry summer like we've had, you dry everything out and then you get a little bit of dry lightning into that area. Then all bets are off,' said John Braun, a professor of statistics at the University of British Columbia, who has published more than a dozen peer-reviewed papers on forest fires.
Braun has disowned the model he used, saying it had fundamental flaws in how it calculates fuel load in the forest and the potential weather patterns it envisions.
'After 15 years, I would have to say I don't think (the model) is trustworthy,' he said.
The problem not only with the old model but even newer, updated ones, he explained, is that they're based on historical weather data, which is becoming increasingly obsolete. Longer periods of drought, higher temperatures and more precipitation coming all at once during big storms produce conditions in the forest that no longer resemble the past.
'What that means is you don't include the unthinkable in your possibilities. And frankly, some of these fires that we've seen in the recent past and including the California fires and things you see in Europe and Australia, these really, I think, are classified as unthinkable,' he said.
'These models are actually incapable of capturing the events that actually are possible but that just haven't happened yet.'
This story is Part 3 in The Coming Firestorm, a three-part series on the growing risk of wildfires fuelled by human-induced climate change.
In Part 1: The next big wildfires are coming —
but Ontario doesn't have nearly enough firefighters
.
In Part 2: A Star reporter
learns to be an Ontario fire ranger
— the province's front line against the next uncontrollable blaze.