(Montreal) According to researchers at Western University in Ontario, it is not one, but two tornadoes that would have made landfall in Quebec during the passage of a system of violent thunderstorms last Thursday.
Posted at 8:50 p.m.
In addition to the Mirabel tornado already confirmed by Environment Canada, experts from the Northern Tornadoes Project (NTP) say they have found evidence of another weak tornado that occurred near Saint-Thomas in Lanaudière.
In an article published on their website on Wednesday, researchers said this second tornado received the lowest intensity rating.
“On July 16 and 17, 2023, a ground and drone survey was conducted by the NTP and documented damage to trees, damage to two barns and the roof of a house. A visible tornado path through crops was also observed,” the researchers said.
As a result of their analyses, the estimated maximum wind speed was set at 130 km/h, the path length at 6.61 km and the maximum path width at 200 m.
In the case of the other tornado, reported by a weather observer at Mirabel Airport, it caused no damage, according to NTP.
Environment Canada meteorologist Peter Kimbell was contacted for comment on the NTP sightings and said the federal weather agency would not release a strength rating for the Mirabel tornado and would not confirm the second Saint Thomas tornado.
However, Environment Canada does not dispute the conclusions of the Northern Tornadoes Project.
In addition to the two tornadoes, NTP has identified five locations in Quebec where the storm experienced downbursts — a phenomenon in which the air descending from a thunderstorm creates strong winds as it hits the surface.
Damage to trees and roofs of several buildings was reported in Lanoraie and Sorel-Tracy. The NTP estimated gusts of 150 km/h in this sector.
Similar phenomena were also recorded near Saint-Jérôme, Sainte-Anne-des-Plaines and Sainte-Sophie and in Saint-Anicet.
Last Thursday, the steamroller of severe thunderstorms moved about 450 kilometers between southern Ottawa and Sainte-Anne-de-la-Pérade, halfway between Trois-Rivières and Quebec.
Rainfall ranged from 50 to 90 millimeters in all affected areas, causing sewage overflows and widespread flooding in several communities.
Another tornado associated with this system has also been confirmed by Environment Canada south of Ottawa.