What is a 'derecho'? Climatologist explains Saturday's powerful storm
The storm that moved across Ontario and Quebec Saturday is known as a “derecho” (da-RAY-cho), a powerful kind of windstorm that is long lasting and far-reaching.
The derecho storm that slashed across southern Ontario and Quebec before moving into Maine left a path of destruction in its wake, and was responsible for at least eight deaths, including three in eastern Ontario.
Environment Canada Senior Climatologist David Phillips explains that a derecho is not a common term.
“It’s not a word we use very often because they don’t occur that often,” he told Newstalk 580 CFRA’s ‘CFRA Live with Andrew Pinsent’ on Sunday. “It’s sort of like a microburst or a thunderstorm but you get a whole army of those. Imagine soldiers lined up and just mowing down the front lines as they move along. Meteorologically, that’s essentially what happens.”
The storm moved into Canada from Michigan at around 11 a.m. Saturday, hitting London, Ont., Kitchener-Waterloo, Toronto, Kingston, and Ottawa, before moving up into Quebec and then to Maine.
“This storm was almost about 1,000 kilometres from Michigan to Maine as it went across Ontario and Quebec. That’s what a derecho is, it’s a long line of very active thunderstorms or microburst kind of situations. Nothing can deter it. It just marches along,” said Phillips.
Phillips said a derecho often has tornado-like or even hurricane-force winds. Ottawa saw wind gusts of up to 120 km/h and other locations saw even stronger winds.
But tornadoes, which are rotational storms, can still be embedded in the generally straight line of a derecho.
“There could be tornadoes embedded in that kind of derecho. I haven’t heard of a tornado report, but it doesn’t mean it can’t produce it,” he explained.
Western University’s Northern Tornadoes Project says it is investigating in the Uxbridge, Ont. area and just south of Ottawa, for evidence of possible tornadoes.
Just last week, the Northern Tornadoes Project confirmed an EF0 landspout tornado in the Casselman area, Ontario’s first tornado of the 2022 season.
Phillips says May can be a fickle month when it comes to the weather.
“You have that combination of warm, humid air that’s possible,” he said, noting the storm moved in when it was 30 degrees with a humidex of 38 on Saturday. “There is always that possibility of warm air in May, but the cold air in May is never too far away.”
It’s when cold, dry air hits warm, moist air that powerful storms can be produced, Phillips said.
“You can get air mass thunderstorms in July, but what you’re getting in May is that combination of the warm air duking it out with the cold air. In the springtime, this is why you can get some violent weather,” Phillips said.
“When you get that kind of one atmosphere changing to another, it’s usually heralded by some wild weather, and there it was.”
CTVNews.ca Top Stories
Chants of 'shame on you' greet guests arriving for the annual White House correspondents' dinner
An election-year roast of U.S. President Joe Biden before journalists, celebrities and politicians at the annual White House correspondents' dinner Saturday.
What is a 'halal mortgage'? Does it make housing more accessible?
The 2024 federal budget announced on April 16 included plans to introduce “halal mortgages” as a way to increase access to home ownership.
Here's where Canadians are living abroad: report
A recent report sheds light on Canadians living abroad--estimated at around four million people in 2016—and the public policies that impact them.
Deadly six-vehicle crash on Highway 400 sparked by road rage incident
One person was killed in a six-vehicle crash on Highway 400 in Innisfil Friday evening.
Opinion I just don't get Taylor Swift
It's one thing to say you like Taylor Swift and her music, but don't blame CNN's AJ Willingham's when she says she just 'doesn't get' the global phenomenon.
Invasive and toxic hammerhead worms make themselves at home in Ontario
Ontario is now home to an invasive and toxic worm species that can grow up to three feet long and can be dangerous to small animals and pets.
Harvey Weinstein hospitalized after return to New York from upstate prison
Harvey Weinstein’s lawyer said Saturday that the onetime movie mogul has been hospitalized for a battery of tests after his return to New York City following an appeals court ruling nullifying his 2020 rape conviction.
'We are declaring our readiness': No decision made yet as Poland declares it's ready to host nuclear weapons
Polish President Andrzej Duda says while no decision has been made around whether Poland will host nuclear weapons as part of an expansion of the NATO alliance’s nuclear sharing program, his country is willing and prepared to do so.
Central Alberta queer groups react to request from Red Deer-South to reinstate Jennifer Johnson to UCP caucus
A number of LGBQT+2s groups in Central Alberta are pushing back against a request from the Red Deer South UCP constituency to reinstate MLA Jennifer Johnson into the UCP caucus.