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
Prince William and Kate release photo of daughter Charlotte to mark ninth birthday
Prince William and his wife Kate released a picture of their daughter Charlotte to mark the princess's ninth birthday on Thursday.
Ontario man loses $1,500 applying for Nexus cards on social media
The trusted traveller program between Canada and the United States is extremely popular and almost two million Canadians have a Nexus card.
NEW Facial reconstruction reveals what a 40-something Neanderthal woman may have looked like
Scientists studying a Neanderthal woman's remains have painstakingly pieced together her skull from 200 bone fragments to understand what she may have looked like.
Concerns about Plexiglas prompt inspections at some Loblaws locations in Ottawa
Inspections are underway at more than one Loblaws location in Ottawa after complaints were filed about tall Plexiglas barriers.
Weight-loss drug Wegovy available in Canada starting May 6
The makers of Ozempic say their weight-loss drug Wegovy will be available to patients in Canada starting Monday.
Five human skeletons, missing hands and feet, found outside house of Nazi leader Hermann Goring
Archeologists have unearthed the skeletons of five people, missing their hands and feet, at a former Nazi military base in Poland.
This Canadian restaurant just lowered its prices. Here's how it did it
A Canadian restaurant lowered its prices this week, and though news of price tags dropping rather than climbing sounds unusual, the business strategy in this case is not, according to experts in the field.
NEW Companies letting customers opt out of Mother's Day ads
In an effort to balance the profitability of Mother's Day with the pain it causes some people, some brands are offering customers the choice to opt out of Mother's Day email advertising.
NEW A mother's hopes to free her son from a Syrian prison is revitalized by a new human rights report
Just days before the seventh anniversary of the day Jack Letts was thrown in prison with thousands of suspected ISIS fighters, his mother, Sally Lane, delivered a small stack of envelopes to the headquarters of Global Affairs Canada in Ottawa.