Emergency crews are cleaning up an Ottawa suburb after a tornado touched down on Thursday with little to no warning.
Residents in Barrhaven, which is about 20 kilometres southwest of downtown Ottawa, continue to deal with the fallout of the twister that damaged at least 125 homes and left a trail of debris across the area.
Over the last few years, the Ottawa area has become familiar with the damage caused by tornadoes – in September 2018, a tornado registered on the intensity scale as an EF-3 ripped through Dunrobin, Ont., injuring 25 people, six of who had to be taken to hospital.
Historically in Canada, tornadoes are most common in the Prairies. However, researchers are noticing tornado occurrences moving more eastward – a “concerning” trend, said Connell Miller, an engineering researcher for the Northern Tornadoes Project at Western University.
“Before, we were seeing that the peak tornado area was the southern part of Saskatchewan, but we’ve been finding it’s shifted eastward, so it’s more in the southern regions of Manitoba, and the Ottawa and (northern Ontario’s) nickel belt region has been getting a lot heavier occurrence than we would have normally expected,” he told Global News.
“Any time we see a shift into the Windsor-to-Quebec City corridor, it’s concerning because the majority of Canadians live in that corridor. If there’s an increase in tornado occurrence there, you’ll see an increase (in damage) where people live instead of the Prairies (where it) tends to be a bit more spread out; you tend to get a lot of tornadoes that just hit crops and nothing else.”
Miller explained that there are studies showing the “Dry Line” meteorological phenomenon – a boundary separating moist and dry air masses in the central United States and Canada, has shifted a few hundred kilometres eastward.
“That Dry Line really affects tornado generation,” he said. “That’s currently the prevailing theory for why these tornadoes are also shifting east.”
The authors of the study The Future of Supercells in the United States may offer a clue behind the shift.
What’s likely happening is as the climate warms, the southwest United States is getting hotter and drier, the authors told The Associated Press in March. Meanwhile, the Gulf of Mexico, which provides the crucial moisture for storms, is getting hotter and the air coming from there is getting unstable.
The hot, dry air puts a stronger cap on where storms would normally brew when air masses collide in springtime. That cap means storms can’t quite boil over as much in the Great Plains, resulting in the pressuring building as the weather front moves east, leading to storms forming later and farther eastward, the authors said.
Another thing the team at Northern Tornadoes Project has noticed is that tornado season is shifting later into the year.
“Before, we would say peak tornado season is around early July to about now, but recent data has shown that’s shifted more into early August,” Miller said.
Northern Tornadoes Project, which started in 2017, noted Canada gets roughly 120 tornadoes per year, Miller said.
The project has two goals: to assess Canada’s true tornado climatology to improve the models the country has for tornado warnings, and to make homes more resilient to tornadoes.
“We’ve been pushing for changes to the building code. So, 95 per cent of the tornadoes that Canada gets are rated as EF-2 or less. In the case of an EF-2 tornado, there’s a good likelihood that you’ll lose the roof of your house because the way that we hold down roofs is just a series of small nails because you’re more focused on the roof not collapsing inwards on the house,” Miller said.
“Research that we’ve done has shown that if we spend an extra $200 to improve the connections … we can prevent the roof from coming off in these EF-2 tornadoes … If we can prevent that from happening, that not only greatly improves the severity of damage that happens in these tornadoes, but improves safety as well because a lot of damages and injuries from these tornadoes are from debris.”
Home improvements aside, Miller suggests Canadians ensure they have an emergency kit prepared in case they are impacted by a tornado, but also says they should be weather aware.
“Be weather aware but not weather anxious,” he said, saying people shouldn’t wait for an emergency alert on their phones to warn of a tornado, they should always be aware of weather risks. “If you have any sort of weather app on your phone, you’ll know if there are severe thunderstorms coming your way and if you know there are severe thunderstorms coming your way, make sure that you have a plan,” he said.
“Have a plan to find a spot in your basement or if you don’t have (a basement), a neighbour’s basement or a suitable shelter if a tornado looks like it’s potentially coming your way. I always suggest don’t be reactive to the things that are happening weather-wise. Be proactive.”
— with files from The Canadian Press and The Associated Press
Comments