'We live on a fire planet': Why spring is the most dangerous time for wildfires
Tinder-dry Winnipeg is approaching a record stretch without significant precipitation
Southern Manitoba is layered in a tinder blanket that has made this spring one of the most dangerous for brush fires, ready to ignite with the slightest spark.
While the situation is critical, and people are urged to be cautious with open flames and flammable materials, we're also trying to suppress a natural process. Fire has always been as much a part of the province's environment as mosquitoes and frostbite.
The truth is, southern Manitoba offers up a perfect fuel source for fires in spring — unless, of course, it's flooded.
"We live on a fire planet. Conditions are just right for fire on the planet Earth and that's what we're trying to deal with all the time," said Brian Amiro, a professor in the department of soil science at the University of Manitoba.
"So every spring in Manitoba, we have a lot of vegetation that has sat dry through several winter months. Things haven't greened up yet and the temperature is rising, sometimes quite rapidly, as happened this week with the mercury hitting 31.4 C.
"All that dried vegetation, grasses especially, are what we call fine fuels."
Those small pieces act like kindling, giving the first flames something to devour before they grow stronger, able to consume larger trees and structures.
As a small fire builds up, it preheats the larger fuels, dries them out and makes them ready to burn, Amiro said.
The drier and windier the conditions, the quicker the flames spread.
"Absolutely, this is the prime time of the year for fires," said Ihor Holowczynsky, assistant chief of fire rescue operations for the Winnipeg Fire Paramedic Service.
"We've flipped the switch and it's suddenly summer, hitting 30 C the other day. Really, it's just waiting for a spark to ignite."
That can be a carelessly tossed cigarette butt, an ember from a firepit, a lightning strike, even some broken glass acting as a magnifier of the sun. Or, perhaps, a spark from a passing train.
The threat is reduced by winters with a lot of snow because that leads to saturated soil conditions in spring and pooling water, which makes those fine fuels too sodden to ignite.
By the time things dry, shrubs and grasses have greened up, making them less prone to ignition. The leaf canopy in urban and forested areas then blocks sunlight, keeping the ground cool and moist.
Historic dry spell
This year, however, Mother Nature threw together the perfect combustible concoction:
- Less than normal snow cover.
- Quick melt.
- High temperatures.
- Dry fuel.
- Low humidity.
- No rain.
Winnipeg is actually knocking on the door of history, in terms of all-time longest dry spells. The longest ever was 47 days in 1976.
This year, there hasn't been any measurable moisture since April 12 when there was a measly 1.2 millimetres. That makes 30 days as of Saturday and there will be a few more yet.
CBC meteorologist John Sauder said there's no sign of any significant precipitation in the forecast for at least a week.
"It's an epic dry spell," he said.
Other than in 1980, which set the second-longest streak at 40 days, you'd have to go back more than 100 years to find a year as dry as this one. There was a streak of 36 days in 1880/81, a streak of 34 days in 1882 and 33 days in 1904.
Fires claim lives, homes
The conditions have led to fires destroying five homes on Little Saskatchewan First Nation and five other buildings in the Interlake — in Fairford and Gypsumville — on May 7.
Crews with the Winnipeg Fire Paramedic Service have responded to 57 grass or brush fires this year so far. There were 85 for the entire year in 2017.
One of the blazes in 2018 has been blamed for the death of two brothers, Randy and Wendell Robinson, band members from Bunibonibee Cree Nation, also known as Oxford House First Nation.
The men, who had moved to Winnipeg, were found badly burned in a fire that scorched a field near Regent Avenue West on May 4.
Settlement to blame
The native grasslands that once dominated much of southern Manitoba, Saskatchewan and Alberta were prone to fires, said Amiro.
"They probably burned every one to five years," he said.
"If you look globally, those areas we call savannahs — North American Great Plains or Prairies, parts of Africa, parts of Australia and South America — are grassland-dominated largely because fire is very common in those areas."
Fires kept forests from growing, by eliminating the shrubs and saplings that sprang up, while herds of bison chowed down on the woody sprouts as well.
When fires passed through, the soil would be recharged with new organic material and a fresh food supply would regrow for the herds. It was a natural process.
Our problem is settlement.
"Because we have people in the way, we end up having this situation of conflict in terms of threats to values at risk, either human life or infrastructure or anything else we're now trying to protect from that fire," said Amiro.
"In southern Manitoba now, we have lots of infrastructure and we have agriculture that has changed the nature of those grasslands."
And as cities expand, suburbs shoulder their way into fields where fires could once burn freely without posing any danger.
Urban areas have flammable materials other than just vegetation, Amiro said.
Homes come with wood frames, fences, decks and other fuel for fires — literally, in terms of gas in vehicles, containers and lawn mowers.
Roads can act as fire breaks, halting the leading edge, but winds can throw embers across the pavement, igniting another fire on the other side.
Fires have benefits, too
Like the grasslands, boreal forests are also historically dominated by fires, burning down once a century, said Amiro.
The process releases nutrients back into the ecosystem, creating a biodiversity by bringing back animals and plants that might not have been able to find food sources in the dense woodland.
A younger forest doesn't evaporate water as readily as an older forest so it can also save soil moisture, Amiro said.
"So there are a lot of ecosystem services that are being driven by this fire."
To allow fire to do provide these benefits, but in a controlled way, governments conduct prescribed burns and target specific areas.
"It could be in a circumstance where we've been suppressing fires for so long that we've changed the nature of the ecosystem," said Amiro. "A prescribed fire can help re-establish those processes and brings back a more normal fire regime."
In some circumstances, such as in national or provincial parks, the burns will be used to eliminate the fine fuels that could help ignite a larger blaze.
Or, in the case of Spruce Woods Provincial Park in April, a prescribed burn was conducted to help the park regenerate species of grasses and woody vegetation that is native to the area and to push back the growth of non-native vegetation.
Fire's own climate
Heat and wind will exacerbate a wild fire but one that grows to a severe state can create its own climate.
The intense energy inside a raging blaze can change the way local winds work, said Amiro. A blaze that fierce can even create its own cumulus clouds — pyro-cumulus — and in some cases, its own lightning and tornado.
A massive fire tornado was caught on camera during wildfires in California in 2008 while the May 2016 fire that swallowed large areas of Fort McMurray, Alta., produced some as well.
Wildfires produce their own wind, called indrafts, that can gust up to 90 kilometres per hour and can often overpower the synoptic or large-scale winds that come from the outside, according to CBC Radio science columnist Torah Kachur.
These indrafts are caused by the hot air rising and cooler air rushing in to take its place. This can cause fires to move in unexpected directions and with unexpected intensity.
The indrafts can become so powerful that the fire burns skywards, throwing flames and burning debris up into the air.
Holowczynsky said crews undergo annual training to deal as much as possible with the unpredictability of fires of all kinds, and to make sure they have an escape plan.
"That's the great danger — that the direction can change quite quickly and you could be in the middle of it before you know it," he said.
"If you're in the fuel, you are the fuel. So you need to be on the burnt side, attacking in a certain position."
The leading edge of a brush fire tends to be narrower as it fans out at the flank. A sudden change in wind direction could shift the flank, making it the new head and turning it into something huge, which can catch crews off-guard, he said.
Manitoba's grassland situation is not the same as the massive forested areas in British Columbia or Alberta, where the flames are leaping from treetop to treetop, Holowczynsky said.
"It doesn't necessarily create its own firestorm, but it still is dangerous in that it travels at an extremely rapid pace."
And when it covers vast areas, the challenge comes in containing the spread of the flames and battling the smoke that impairs visibility, he said.
For the most part, in an uninhabited field of grass, crews can take time and be cautious. There is far less urgency than when flames are lapping at the edge of a community.
"Embers are carried on the wind and it doesn't take long for them to land in somebody's yard," Holowczynsky said.
How that homeowner has prepared their yard can make the different between an ember becoming a house fire, or being simply snuffed out.
To that end, WFPS crews will be visiting certain Winnipeg neighbourhoods near large fields on the edges of the city, starting in Charleswood this weekend.
It's about making people aware of how to increase their safety because "the best fire's the one that didn't start," Holowczynsky said.
Simple things people can do, like clearing leaves, debris and brush, and not storing combustibles in the yard, "goes a long way to protecting themselves and their families."
Other suggestions include:
- Keeping shrubs and trees near buildings trimmed and watered.
- Disposing of leaves, lumber and yard waste properly and promptly.
- Ensuring that shrubs and flower beds are regularly cleared of dead plant matter.
- Not extinguishing cigars or cigarettes in potted plants, as potting soil and peat moss can be flammable.
- Keeping firewood stored away from the house or garage.
"If you live close to wildland areas, we recommend that you keep a 10-metre buffer zone around your house," said Tom Wallace, deputy chief of support services with WFPS.
Those suggestions also apply in the fall, when the fire risk spikes again when the grasses die off and turn brown again.
However, the threat is tempered somewhat at that time because the weather typically cools off quicker.
But it's always better to be safe than sorry, said Holowczynsky.
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