When Canadian tornado expert David Sills examined the forecast Saturday morning, he never expected a storm line heading to Windsor, Ont., To soon intensify in Canada’s first gorge in decades, wreaking havoc in southern Ontario. and Quebec.
Sils, who is the CEO of Northern Tornado Project at Western University, was outside working in the yard of his home in London, Ont., when he heard a rumble in the distance; he couldn’t believe the storm line was still so active.
I think, What? Why is this still going on?
He went back inside to study the forecast, and then the storm came to his doorstep.
“Suddenly it hit and it’s just like a hurricane,” Sils said. “It’s getting louder and louder… I watched a tree fall on my neighbor’s roof across the street.”
Then he realized that it was no ordinary thunderstorm.
Strong winds lift the dirt before the storm arrives in Saint-Bernard-de-Mishoville, Que. (Daniel Thomas / Radio Canada)
An ominous wall of wind and rain
Dere, pronounced deh-RAY-cho, is a long-lasting, fast-moving thunderstorm that causes widespread wind damage. This particular storm system was powered by a heat dome over the eastern United States.
According to Sils, the system formed south of Chicago on Saturday morning, after which it crossed the border in the Windsor area, where it began to cause damage.
By the time he arrived in Kitchener, Sils said the thunderstorm had produced gusts of up to 132 km / h.
Unlike the whirling winds of a hurricane or tornado, the winds of a tree are straight. This does not mean that it is less harmful; its winds can knock down trees and lift roofs. Another feature of derecho is that unlike the slow build-up of a supercellular thunderstorm, the business end of derecho is ahead.
That’s why when you witness a tree, Steele said, it often looks like an ominous wall of wind and rain.
“When it hits, the worst is usually within minutes of hitting,” he said.
Part of a utility pole lies on an alley, along with the roof of an iron shop that was lifted by extreme winds during Saturday’s storm, in the Hammond community of Clarence-Rockland, Ont. (Justin Tang / Canadian Press)
Even worse, this destructive wall of wind is that it can sometimes produce a tornado.
“Indeed, it’s just a spectrum of wind that affects a long area,” Sils said.
So far, field teams with the Northern Tornadoes project have identified at least one EF2 tornado that struck Uxbridge, Ont., With wind speeds of up to 195 km / h.
The team is investigating at least four other possible tornadoes in southern Ottawa, London, Ont., And Rowden, Que.
Sils said he expected there could be more.
Even so, “most of the damage is caused by straight winds,” said meteorologist Peter Kimball, warning of Environment Canada’s readiness.
He said Ottawa and Toronto airports also reported winds of 120 km / h.
Rare event: Canada ‘s first gorge since 1999
The last series of derechos to hit Canada was in the 1990s, including one in 1999. According to the US National Oceanic and Atmospheric Administrationthis storm cut through Thunder Bay and sparsely populated areas of northern Ontario before crossing into Quebec, where it killed a man, felled trees, damaged buildings and capsized boats in the Montreal area.
“It’s the widespread nature of derecho that can really cause chaos in the city,” Sils said.
What made Saturday’s storm particularly unfortunate was that several city centers were directly in its path.
“It was an unusual event because it affected the most populous part of Canada,” Kimbel said.
The system was formed south of Chicago on Saturday morning and then moved through Ontario, according to tornado expert David Sils. (Environment and Climate Change Canada / CBC News)
Environment and Climate Change Canada has signaled a strong thunderstorm, triggering cell phone alarms on people in Ontario and Quebec. This was the first time a new feature had been tested that allowed the forecaster to trigger a warning of extreme thunderstorms with strong winds.
“This is the first time they’ve done this and it’s probably saving lives,” Sils said.
Yet the storm left a trail of destruction, killing 10 people and leaving about 900,000 homes and businesses without electricity in Ontario and Quebec at its peak. He continued all the way to Maine, where there were also reports of damage.
Climate change may lead to more gorges
It is difficult to determine whether a rare event could be linked to climate change. Because derechos are so rare in Canada, Sils said it is impossible to say whether they are increasing or not.
But, he said, the ingredients needed to form a tree “may come together more often” as a result of the effects of climate change.
Trees occur when there is a lot of heat and moisture and they are often associated with heat domes. Sils said the climate forecast suggests a warmer atmosphere that will creep north, which means it’s the kind of storm Canadians can expect to see more of in the future.
Aerial photos taken by a drone show the aftermath of Saturday’s storm in Uxbridge, Ont. (Sue Reed / CBC News)
There is always something to be learned from extreme weather events, Sils said, and a key conclusion for him after this storm is that computer modeling must catch up.
“There weren’t many indications in the models of this big gorge that was coming,” he said.
“The computer models we rely on to warn us of such events have a long way to go.”
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