A dangerous combination of weather conditions was at play Saturday afternoon when a deadly fire engulfed a training exercise at CFB Wainwright in east-central Alberta, killing four soldiers and severely injuring dozens more, weather and wildfire experts say.
That morning, Environment Canada had issued yellow alerts for much of southern and eastern Alberta because of strong winds forecast to reach up to 100 km/h and an incoming cold front that could cause abrupt changes in wind direction.
Before the cold front reached the area, the temperature in Wainwright climbed to over 23 C under sunny skies.
“Conditions were extreme,” said Mike Flannigan, a professor of wildland fires at Thompson Rivers University in Kamloops, B.C., who runs the Canada fire weather outlook. “Things were dry. Any fires that started would have spread rapidly and would be intense and that’s pretty well what happened.”
What we know so far about fast-moving fire that killed 4, injured dozens at CFB Wainwright
Flannigan said NASA satellite data indicate a fire was burning near the base by around 2 p.m. The Canadian Forest Fire Weather Index shows that fire conditions across the Canadian prairies, including southern and central Alberta, ranged from very high to extreme.
Around 4 p.m., a cold front moved through the area, bringing a roughly 10 C drop in temperature and a sharp shift in wind direction, Flannigan said. He said the shift pushed the fire northwest toward the training area.
Canadian Armed Forces Maj.-Gen. Wade Rutland, inaugural commander of the revitalized 1st Canadian Division, told reporters Sunday that the fire began as a grassfire and spread rapidly around 4 p.m. as the wind direction changed.
Rutland said range control at the base were aware about a fire for several hours but decided training could carry on “for a certain amount of time.”
That day, soldiers were throwing hand grenades on a grenade range, he said, while others were conducting a “section attack,” in which 10 soldiers attack a simulated enemy.
Rutland said it is not yet known what exactly caused the fire. “Quite frankly, it could have been any of that or none of it,” he said.
The major-general said troops described the fire as covering a distance of a kilometre in under a minute, with the fire suddenly “right on top of them.”
“This was uncommon, rapid, and I certainly hadn’t seen anything like it,” he said, adding that conditions for most of the day were “within standard procedures to conduct training exercises” with wind gusts below 50 km/h.
However, meteorological and wildfire experts say the combination of dry fuels, low humidity and strong winds created conditions favourable to rapid fire spread. Heavy wind gusts of over 80 km/h had also been forecast for the area later that day.
“This was a very dangerous setup,” said Jonathan Porter, chief meteorologist for AccuWeather, a commercial weather forecasting company.
Porter says the company issued a warning to its business customers in the Wainwright area about a risk for high winds around 2:30 p.m. MT.
In addition to the strong wind, Porter said humidity was low, at about 20 per cent, creating “an ideal setup for wildfires to spread.”
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Flannigan of Thompson Rivers University had a similar assessment of the day’s conditions, noting any fire ignited at the time would have spread quickly and intensely.
But those conditions were forecast and were not necessarily unusual for the area at this time of year, he said.
“You do get windy conditions and fall is the time for them,” Flannigan said. He added that heavy rain this spring had caused abundant grass growth, which, after drying this month, created a large amount of fuel for fire to spread.
While grass fires spread more quickly than forest fires, it’s unlikely the fire at CFB Wainwright travelled one kilometre in under a minute, Flannigan said — unless it merged with another fire or ignited unexploded ammunitions.
According to Natural Resources Canada, grass fires can travel up to 12 km/h and their flames can reach up to 10 metres high.
Flannigan noted their speed typically reaches roughly 10 per cent of the speed of the wind that carries them.
A Wainwright Fire Rescue vehicle is seen in Wainwright, Alta., on Sunday as crews continued responding to the aftermath of the deadly fire at CFB Wainwright. (Jennifer Gauthier/Reuters)
In response to questions from CBC about the weather conditions and the response at CFB Wainwright at the time of the fire, the Department of National Defence said in an emailed statement that military police and the Canadian Forces National Investigation Service are conducting investigations in Wainwright and elsewhere in Alberta.
“The investigation remains active, and commenting on specific details at this stage would be inappropriate,” spokesperson Kened Sadiku said.
Flannigan said he hopes the incident leads to better wildfire warning systems in Canada and within the military.
“One thing I can say is that grass fires are dangerous,” he said. “Any fire we have to treat with respect.”
Porter said he expects the Armed Forces’ investigation to examine what actions were or were not taken in response to weather warnings “issued well in advance” and whether those warnings reached the people making decisions about the exercise.
“A key part of this investigation is going to be what actions were taken based upon the high wind warnings that were issued in that area,” he said.
It’s not uncommon for troops to continue training even after flames spark nearby, says Scott Clancy, a retired major-general in the Royal Canadian Air Force and Canadian Armed Forces.
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Clancy told CBC News that soldiers will often continue field training exercises when fires start, noting that fires are routinely managed by military range control.
He said Wainwright is a very large base and a decision to “carry on” would have been made by range control officers who were managing exercises on site Saturday.
The investigation to come will “look at the leadership, the culture that was created around that leadership, the orders, the safety regulations [and] the specific decisions to carry on training,” he said.
“Wildfires … can be smouldering low and then a few minutes later be wild blazing fires,” Clancy said.
