Wildfires that have torched huge areas of forest and devastated small communities are also sending smoke far and wide, prompting air quality warnings in distant cities and heated political rhetoric from the U.S.
This year’s fire season has forced more than a dozen communities and areas to evacuate in recent days, including 10 First Nations communities across northern Ontario.
But it’s the smoke travelling across borders, causing hazy skies as far away as New York City, that has drawn the ire of some politicians.
U.S. President Donald Trump lashed out at Canada for smoke “poisoning” American air, and even suggested the Canadian government should “pay some damages.”
At the same time, smoke from fires raging across the northwestern U.S. has made its way into B.C., as Western Canada contends with its own escalation in fire outbreaks.
With blazes across B.C., the Northwest Territories and northern Saskatchewan, the haze and smell of smoke has been hanging over cities like Edmonton and Calgary this week.
Experts who spoke with CBC News say there’s nothing particularly unusual about this summer’s smoke patterns, despite the inflammatory political discourse. But they say wildfires are getting worse, and that’s not likely to stop on either side of the border.
How does smoke from Ontario reach New York City?
The short and obvious answer is that it travels with the wind.
But Brian Wiens, research manager with the Canada Wildfire Network, says the intensity of a fire will affect just how high its smoke goes into the atmosphere and how far it’s able to travel.
“A really, really hot fire is going to send it really high into the atmosphere, which allows that smoke to travel thousands of kilometres,” he said.
“It’s not at all unusual for smoke from North American fires to travel all the way over to Europe and, similarly, fires from Eastern Asia or Russia travel all the way over into North America.”
Wiens says the smoke dilutes the further it travels from the source, but it can linger until wind flow changes or rain washes it out.
Smoke can get trapped for weeks in communities situated in deep valleys, which are common in B.C., he said.
An entire B.C. town near the border of Alberta remains under an evacuation alert due to an out-of-control wildfire. The Matthew Creek wildfire is about 10 kilometres west of Kimberley, home to more than 8,000 people.
Kent Moore, a professor of atmospheric physics at the University of Toronto, says smoke from the Ontario fires has made it to Greenland.
He says all kinds of pollutants travel both ways across the Canada-U.S. border, noting as one example that Ontario gets polluted air from American coal-fired power plants.
“Pollution in general kind of moves around with the air currents and it doesn’t stop at boundaries,” he said.
Why does the sky turn orange?
Videos from city dwellers experiencing heavy smoke often show eerie, orange- or yellow-tinged skies, with people saying how they feel like they’re in a sci-fi film or an apocalyptic scenario.
Moore explains that particulates in the air cause this phenomenon by scattering blue light, allowing other colours to come through more prominently.
“Blue light, because of its wavelength, is scattered by this particulate matter in the atmosphere. Red light isn’t,” he said.
“That’s why the sun tends to appear red when we have these wildfire events, because there’s so much smoke in the air that it scatters all the blue light away.”
He compares this effect to sunsets, which often appear reddish because the sun is low and close to the horizon, so its light has a longer distance to travel to your eyes.
Andrew Chang explains how Ontario wildfire smoke is able to change the colour of the air in cities more than a thousand kilometres away, and the health risks of inhaling it.
Images provided by The Canadian Press, Reuters, Adobe Stock and Getty Images
Can’t we just put out all the fires?
“This is the third consecutive year we have had to write to Canadian officials about a crisis that Canada has the tools to prevent and has chosen not to,” four Michigan Republicans wrote in a letter last week, calling out Canada for a perceived lack of action in combatting wildfires.
Setting aside that the U.S. is dealing with its own vicious wildfire season, many Americans might not understand the vastness of the northern Canadian wilderness.
“Much of Canada and many of the areas where these large fires producing smoke are burning, including in northern Ontario and in the Northwest Territories, are quite remote and not accessible,” says Jen Baron, assistant professor of fire ecology at the University of British Columbia.
“It’s not easy, or possible in many cases, to put firefighters on the ground.”
Wiens says fires that threaten human lives and infrastructure are the priority for limited firefighting resources. Serious logistical challenges — like having to fly a plane two hours to drop one load of retardant on a blaze, for example — are partly why the biggest fires usually tend to burn across unpopulated areas.
If human lives or infrastructure aren’t threatened, Wiens says, it’s simply not worth the investment to fight large fires.
“The amount of heat that’s released by a fire is so mind boggling that, basically, they come to the point where there’s nothing you can do to fight them,” Wiens said.
“The best you can to do is help nudge them one direction or the other, and of course there’s no point to doing that if it’s way in the middle of nowhere.”
Why is the problem getting worse?
All of the experts who spoke with CBC News said this year’s situation is reminiscent of 2023, when smoke from Canadian fires also drifted through the U.S. Eastern Seaboard.
They all said climate change is the driving force behind the growing problems of wildfires and smoke across North America in recent years.
That’s because hot, dry and windy conditions are becoming more common as the climate warms, leading to more drought and more fuel. So when fires hit, they have the potential to burn hotter and faster.
Northern Canada, in particular, is warming faster than the global average.
“It’s not just increases in the average temperature by a couple degrees, but these really extreme heat dome events and really large drought conditions that are are driving increased fire behaviour,” Baron said. “And when fires burn more severely, they tend to produce more smoke.”
As annoying — and harmful — as smoke can be for distant city dwellers, Baron says it’s important to remember the devastation the fires are causing in communities across Canada.
“Many of them have lost significant amounts of infrastructure, have lost their communities,” she said. “As challenging as it is to be under high levels of smoke, I think it’s important to keep in mind the source of that smoke.”
