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
American millionaire Jonathan Lehrer denied bail after being charged with killing Canadian couple
American millionaire Jonathan Lehrer, one of two men charged in the killings of a Canadian couple in Dominica, has been denied bail.
LeBlanc says he plans to run in next election, under Trudeau's leadership
Cabinet minister Dominic LeBlanc says he plans to run in the next election as a candidate under Prime Minister Justin Trudeau's leadership, amid questions about his rumoured interest in succeeding his longtime friend for the top job.
Sports columnist apologizes for 'oafish' comments directed at Caitlin Clark. The controversy isn’t over
A male columnist has apologized for a cringeworthy moment during former University of Iowa superstar and college basketball’s highest scorer Caitlin Clark’s first news conference as an Indiana Fever player.
Health Canada to change sperm donor screening rules for men who have sex with men
Health Canada will change its longstanding policy restricting gay and bisexual men from donating to sperm banks in Canada, CTV News has learned. The federal health agency has adopted a revised directive removing the ban on gay, bisexual and other men who have sex with men, effective May 8.
U.S. vetoes a widely supported UN resolution backing full membership for Palestine
The United States has vetoed a widely backed UN resolution that would have paved the way for full United Nations membership for the state of Palestine.
Bayer recalls hydraSense baby product over 'potential contamination'
Bayer announced Thursday it is recalling two lots of its hydraSense Baby Nasal Care Easydose due to a potential contamination.
N.L. gardening store revives 19th century seed-packing machine
Technology from the 19th century has been brought out of retirement at a Newfoundland gardening store, as staff look for all the help they can get to fill orders during a busy season.
Cat found on Toronto Pearson airport runway 3 days after going missing
Kevin the cat has been reunited with his family after enduring a harrowing three-day ordeal while lost at Toronto Pearson International Airport earlier this week.
Grandparent scam suspects had ties to Italian organized crime, police allege
A group of suspects that allegedly defrauded seniors across Ontario and other parts of Canada using a so-called emergency grandparent scam appear to have ties to 'Italian traditional organized crime,' according to an investigator involved in the OPP-led probe.