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The fire that ripped through Jasper came in fast and ferocious. Events moved quickly — there was a surprise evacuation of 25,000 people late Monday night and less than 48 hours later, a wildfire south of Jasper breached the townsite.
Now, many people are asking: How did it get so out of control?
The answer isn’t simple. Experts say the flames of this monster fire were fanned by a combination of extreme heat, drought, and an abundance of flammable materials.
Hot, dry and a deadly jet stream
In the weeks leading up to the wildfire, Jasper was in the midst of a heat wave, with most days soaring into the 30s. On Sunday, July 21 — the day before the evacuation — it reached 38 C.
It has also been particularly dry.
In the first three weeks of July, less than one millimetre of rain had fallen in Jasper, according to Environment Canada statistics. Normal precipitation for the month is about 52 millimetres, based on data from 1991 to 2020.
Those types of hot and dry conditions will increasingly become more common in Alberta, said Mike Flannigan, professor of wildland fires at Thompson River University in Kamloops, B.C.
“Future modelling suggests during our fire season in Canada at least, we’re going to be actually drier than historic norms … there’s no rain to help us out of this situation, bottom line,” said Flannigan.
Jet streams — air currents that flow from east to west across the globe — play a major role in the weather conditions Alberta experiences. When the jet stream kinks, it creates ridges where air sinks and towns or cities within a ridge will experience warm and dry conditions.
“That’s what brought the heat dome in 2021, and brought [the] extended, hot dry period in 2023,” said Flannigan.
“Eventually that ridge breaks down or moves off and it’s often associated with a cold front. And cold fronts are notoriously extreme situations for fire.”
These were the conditions Jasper experienced in the weeks leading up to the wildfire. The cold front brought wind and lightning, which combined with the heat to create a perfect storm for fire.
Officials believe the fire that breached Jasper from the south side of town was likely caused by lightning.
As the fire grew and travelled north, Flannigan believes it picked up energy to form a pyrocumulonimbus cloud — a thunderstorm cloud that can create its own weather.
Supporting his theory is the description from a Parks Canada executive about the “hell on Earth” conditions that included a 100-metre-high wall of flames and burning pine cone projectiles.
Flannigan says pyro storms, as they’re called, are becoming increasingly common in Canada.
Before 2023, Flannigan says the global record for pyro storms was 102, including 50 in Canada.
“2023 came along, and Canada had 140, so almost triple our previous record and more than the previous global record,” said Flannigan.
Flannigan says there has been an increase in pyrocumulonimbus fires in Western Canada, the United States and Siberia. — places that have plenty of dry vegetation that ignites easily.
Pine beetle decimation
Alberta is in the midst of a drought, conditions that have left forests tinder dry. Experts say these conditions point to an environmental shift caused by climate change.
It has also left Alberta’s forests vulnerable to the spreading infestation of mountain pine beetles, according to Parks Canada.
“Climate change is exacerbating the spread of invasive species and disease and impacts are expected to worsen in the coming years,” states the 2017 Parks Canada management plan for Jasper National Park.
The report says the pine beetle infestation has decimated healthy trees in Alberta’s forests. Those dead, dry trees amplify the threat of wildfires.
“You have a pretty mature forest, in the case of Jasper, you’ve got a huge amount of beetle-killed timber, and that’s basically standing firewood,” said John Vaillant, author of Fire Weather: The Making of a Beast.
And with warmer Alberta winters, the risk of pine beetle infestations isn’t going away anytime soon.
“Now they’re surviving through the winter and they’re able to amplify and multiply — we’ve seen thousands of square kilometres of B.C. and Alberta destroyed by beetle infestation,” said Vaillant.
Flannigan says the national park has been taking steps, such as prescribed burns and removing dry vegetation, to reduce this risk.
Our forests are meant to burn, he added.
“It’s the cycle of life,” said Flannigan. “As much as possible, we should try and work with Mother Nature and that means allowing fire on the landscape, or doing prescribed fire on the landscape as much as possible so that it’s more controlled and manageable.”
The fire in the Jasper townsite has been extinguished, but it continues to burn elsewhere in the national park. As of July 26, it had burned an estimated 32,000 hectares, making it the largest fire the park has seen in over a century.
Challenges of the townsite
The Jasper townsite is flanked by mountains and sits in the confluence of three valleys. According to Flannigan, that geography only further increases Jasper’s susceptibility to fire.
“Fires love valleys,” said Flannigan. “They run up and down valleys, it’s a pathway, it’s a corridor for them. … Jasper the town and the national park have known for decades it’s a high-risk area.”
How the town was built also adds to the fire risk, experts say.
“We live in a much more flammable world now,” said Vaillant. “Places that we thought of as being relatively protected or even impervious to fire are no longer.”
Modern construction materials are highly flammable, he said.
“There’s a lot of petroleum products in modern buildings. Not just in tar shingle roofs and vinyl siding but in all the laminates and glues that [hold] plywoods and floor coverings, even in our mattresses,” said Vaillant.
Alberta officials say an estimated one-third of the structures in Jasper are destroyed, including the St. Mary and St. George Anglican Church, built in 1928.
When faced with flames, these materials can become explosive, Vaillant said.
“If you heat up vinyl siding or tar shingle roofs to 300 or 400 C … when embers land on it — when fire touches it — it doesn’t just start to smoulder or burn, it will actually burst into flames.”
That rapid ignition of building materials is a characteristic of what he calls a “21st-century fire.”
For Fire Weather, Vaillant interviewed people from Australia, California and Alberta. A common observation was how fast fire ripped through their city or town.
“All of them were shocked by the speed of the fire, how fast it moved, how quickly it appeared to be over the hill or on the horizon,” said Vaillant.
“Really within minutes or half an hour, they were running for their lives.”
CBC Explains
Fire from fire: How wildfires can create their own weather and lightning
One way Jasper is trying to reduce its risk is by practicing FireSmart principles, which include recommendations to protect homes by keeping yards clear from dead vegetation or using less-flammable building materials.
Flannigan warns that these principles can only work if adopted by the entire community.
“You’re as strong as your weakest link. So that is part of the issue with FireSmart, it needs to be across-the-board mandatory,” said Flannigan.
“You could have one house that is fire smart, but right beside it is another house that’s not fire smart. [When the] rain of burning embers comes down … the house next door catches on fire and then it spreads structure to structure.”
Source: cbc
