OTTAWA A team of investigators are assessing the extent of the damage in the aftermath of the tornado that hit Barrhaven, a suburb in south Ottawa on Thursday. Researchers say it moved fast and that multiple homes had structural damage.
“Imagine taking your house and flipping it upside down, while hanging weights off of the roof and then shaking it. That’s a good representation of the type of uplift forces that act on residential structures,” explained Connell Miller.
Miller is one of the lead engineering researchers with Western University’s Northern Tornadoes Project, overseeing the team assessing damage in Ottawa.
About 125 homes were damaged by the tornado, the city said on Thursday, in Umbra Place, Watercolours Way, Perseus Way, Proxima Terrace, Jockvale Road and Exeter Drive.
“Typical damage seen includes a loss of shingles and cladding, uplift of roof decking, and broken windows,” said Miller, adding that the researchers also found many damaged sheds, fences and trees.
“The tornado … travelled across the ground quickly,” according to Miller, but the translational speed of the tornado doesn’t determine the intensity of the damage.
“Structures would have experienced the peak wind speed for only a short period of time. Thankfully in the Barrhaven tornado, it only got to the point of losing roof decking.”
Typical damage on a house tends to follow a certain pattern, Miller explained; first you lose your shingles or siding, then the roof decking, then the roof trusses, then the walls collapse, and finally everything gets swept away.
“It doesn’t take long for a tornado to do serious damage to residential structures.”
Contractors and their cars crowded Marek Way on Friday, one of the streets that was hardest hit.
Some stood on roofs throwing scattered shingles to the ground. Others threw large pieces of plywood in trailers. One lifted a ragged hockey net onto a bulldozer’s front blade.
A few residents watched from their porches or driveways as debris from their torn-up homes was collected.
Basim and Aya Refat, along with their two children, were forced to vacate their house on the street due to extensive damage.
They said they are staying in hotel accommodations paid for by their landlord, and don’t expect to be able to return home for a few months.
Aya Refat said she and her two young daughters huddled under a table and barricaded themselves in with a chair as the tornado swept through. She covered her daughters with a blanket to protect them from flying glass.
“So scary. I couldn’t see anything,” she recounted on Friday. “Everything was going away. The floor was moving. The window was broken.”
Aaron Jaffe, an engineering researcher who works with Miller, said the research is in its early stages but the tornado appears to have had a path more than 100 metres wide and several kilometres long.
Jaffe said they are in the process of evaluating the tornado through the Enhanced Fujita Scale — a scale used to measure the severity of tornadoes in Canada and the U.S.
He said the early indications suggest Thursday’s storm may have produced an EF-1 or EF-2 tornado, which can produce winds between 138 and 217 km/h and cause moderate to strong damage.
“The recent EF4 tornado in Didsbury, Alberta had houses that had a total collapse of walls, which is close to as bad as it gets,” added Miller.
The July 1 Didsbury EF4 tornado was one of the strongest and most destructive recorded tornadoes in Canada.
Western’s Northern Tornadoes Project (NTP) recorded 117 tornadoes across Canada during the 2022 season.