Residents watch the McDougall Creek wildfire in West Kelowna, B.C., on Aug. 17.DARREN HULL/AFP/Getty Images
Wildfires raging across Canada have torched more territory than ever before, but lightning – the cause of about half these blazes over the years – has been striking the ground at a rate well below average.
New federal data shared with The Globe and Mail make clear that drought is a main driver of this destruction: The parched land is primed to ignite because Canada is experiencing its driest spring and summer since Ottawa began mapping the precipitation hitting every corner of the country in 2000.
Gabor Fricska, a Kelowna, B.C.-based supervisor with Environment and Climate Change Canada, oversees the sharing of data from the federal lightning detection network with local authorities. He said the intense drought in many parts of the country means fewer strikes can cause just as much or more damage than in past wildfire seasons. The desiccation also means there is less moisture to feed the convective clouds that spawn lightning, said Mr. Fricska, who has been mapping weather for the federal government for more than three decades.
“It’s the drought that’s really set the table for everything. When it’s this dry you don’t need a lot of sparks, and the sparks that you do get are pretty efficient at starting a wildfire.”
Lightning doesn’t always hit objects on the ground or the Earth itself in a single clean emoji-like bolt. Rather, one flash often produces a stroke or two that meet dirt, bringing 500,000 times the power flowing through the electrical outlets of the average Canadian home. Mr. Fricska said he has observed up to seven of these strokes exploding from the same lightning flash at great distances apart. A third stroke that hit the northern side of Kelowna in May, 2020, for example, was more than a kilometre away from the other two, he said.
As of Sept. 5, roughly 3.15 million strokes of lightning have touched the ground from the clouds this year, according to the Canadian Lightning Detection Network, a constellation of data sources the federal government uses to monitor the natural phenomenon. That is well below the average of 3.71 million strokes up to this point in the year, placing 2023 as the third-lowest for total strikes during this span of months since the network began tracking lightning this way in 2002, Mr. Fricska said.
In British Columbia, where more than 80 per cent of the province’s river basins are experiencing high to extreme levels of drought, there have been 290,496 strokes to date this year – just over 8,000 strokes above the average of the past two decades, he added.
In August, federal officials forecast that this year’s brutal wildfire season would continue into this month. So far, an estimated 16.5 million hectares have been burned across the country, dwarfing the 10-year average of two million hectares. Tens of thousands of people are only now returning home after evacuations in B.C. and the Northwest Territories, with thousands still ready to leave their homes at a moment’s notice if their communities are further threatened by nearby fires.
More than a hundred times this year, a Canadian forest fire has become so intense and generated so much smoke it has created its own weather system, which is known as a pyrocumulonimbus event – or, as NASA has called it, “the fire-breathing dragon of clouds.” These hellacious storms also produce lots of lightning: When a pyrocumulonimbus cloud hovered near Kamloops in June, 2021, it sent down 7,000 strokes that started 30 to 40 fires within a matter of hours, according to Mike Flannigan, a wildfire expert at Thompson Rivers University.
Several massive fires still burning in B.C. were started by lightning, including the PEI-sized Donnie Creek wildfire, which has been out of control since igniting near Prince George, B.C., on May 12. The province is also facing the worst drought in its recorded history, leading academics and First Nations leaders to call for urgent government reforms to protect fresh water on the West Coast as climate change lengthens summers and makes weather more volatile.
A single flash of lightning can produce multiple strokes that contact the ground. Environment and Climate Change Canada observed a hit on the northern side of Kelowna in May, 2020, more than a kilometre away from the previous two strikes.
Erika Berg, a fire information officer with the BC Wildfire Service, said in a typical year slightly less than two-thirds of the fires on Canada’s West Coast are started by lightning, with humans accounting for the rest (and usually during the shoulder seasons). This year, her agency has confirmed 1,450 fires were caused by lightning, 450 by people and 120 by unknown sources.
Throughout the summer, provincial officials periodically told residents that only atmospheric rivers of rain could meaningfully affect the drought levels and lower the risk of further fires. Colder fronts often brought a day or two of rain, but also higher winds and more lightning.
Even during steady rain, lightning can strike a giant conifer, travel down its trunk and ignite its roots, leaving that fuel source to smoulder under the tree canopy until conditions dry and the needles or other underbrush at the base ignite and start a forest fire. These “holdover fires” are reasonably common, and on average jump from under the ground to above within a day of the lightning hitting, according to a BC Wildfire Service research paper shared with Mr. Fricska.
These holdover fires have started as long as 22 days after the initial bolt hits, he said.
“If conditions dry out, weather warms up, humidity drops, wind picks up, then the fire comes to light and that’s when it might be discovered.”
Mr. Fricska first observed the awesome power of lightning – and the calamity it can sow – during his childhood in the province.
“I remember, as a kid, driving down from Northern B.C. in 1985 and going through a wall of smoke and the sun looking red.”
With a report from Jane Skrypnek