The Current - Tornadoes -- and warnings -- are on the rise, here's why

Episode Date: July 17, 2026

Canada is on track for a historic tornado season, both when it comes to funnel clouds making land fall, and the number of warnings sent out to Canadians. Dave Sills of the Northern Tornado Project explains what's causing the summer storms, and what needs to change to make tracking them more accurate.

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Hello, I'm Matt Galloway, and this is the current podcast. Does it feel like you're getting more and more tornado warnings? We have a severe thunderstorm risk, including the potential for large hail and isolated tornadoes. Severe thunderstorm watch. Then, in this gray zone, you have a tornado watch. Two tornadoes touchdown between Edgerton and Dilberry Provincial Park. Oh, look at there, right there. This tornado was 30 kilometers southeast of Winnipeg, another one 50 kilometers south of the city.

Those tornado reports, watches, and warnings were all issued over the past three weeks. Tornado warnings in Canada have doubled since 2024, and the number of actual tornadoes themselves is on the rise as well. So what's causing them and are the warnings worth paying attention to? Dave Sills is the director of the Northern Tornadoes Project at the Canadian Severe Storms Lab at Western University. University in London, Ontario. Dave, good morning. Good morning, Pia. Can we just start with actual tornadoes? How is this year thus far comparing with previous years? Right. Well, 77 tornadoes across the country so far. The 30-year average is 65, so well above average. But the real story has been on the prairies.

64 tornadoes so far, you know, really midway through the season. And we basically, if we go back to 1980, which is the beginning of our high-quality data set, there's not another year like that. The closest is 62 tornadoes in 1991. So we're looking at record numbers here on the prairies. And, you know, in the east, it's been 13 tornadoes. So really the action has been on the prairies this year. And you said season, how far are we into tornado season? Right. Well, usually it's June, July, August, right across Canada, those are the busiest months, which is different in the U.S. they have different peaks because of, you know, different seasons down there. But across Canada, it's June, July, August, and with July being the peak.

So we're really just, you know, halfway through the season here, and we've got big numbers already. So the big question is, why are we seeing more this year? Well, yeah, some years you don't see nearly as many as this. But this year, we've had a setup where we've had a system parked over the western U.S., a heat dome. it's been pretty persistent and all of these instability collects under that heat dome. There's not a lot of thunderstorms right under it, but along the northern edge is where all that instability escapes and you get thunderstorms building up. And of course, the prairies have been right under that northern edge for a long time now.

And so that means they've been getting hit with wave after wave of severe storms and that includes tornadoes. It hasn't been the same story in the east. We've been on kind of the northeast side of that heat dome. We're seeing the effects of that heat right now. But for most of the season, we've been on the less favorable side of that heat dome and just haven't seen the same level of storm activity. You know, the last couple of weeks, we've heard it there in those news things, but my phone has said so many alerts about tornado warnings and watches.

I've been like, does this happen every year? You've told us, no, this is a big year. But I want to talk about the warning system. Where are we at in terms of the warnings? They've doubled since 2024 as well, the warnings? You know, it's been interesting because one of the things we're doing at the Northern Tornadoes project is we actually conduct performance assessments of the warning program. So the Tornado Warning Program. We started this back in 2022, and we looked at 2019 to 2021 over those years, how well did the tornado warning program do?

And the picture wasn't a very pretty one. It was a failing grade, basically. and that's using targets from Environment Canada themselves, how they measure their success. So we knew there were improvements to be made. We made recommendations. And one of them was, statistically, you just couldn't get better unless you issued more.

And when we did the report card again the next year, they had doubled the number of tornado watches, number of tornado warnings, and now they were getting a passing grade. So that's what it took. And yes, it results in more false alarms. and those can be managed, but the main thing is not to miss the big ones. There were too many events where we'd get on site to do the survey of the damage,

and the people said, well, we didn't get a warning or we got a warning, just as we were standing out in the street talking to the neighbors about the damage. So let me pick up on two things you said there. The first thing is how do forecast to determine if a watch or a warning needs to be issued? Sure. Yeah, there are definitely two phases. there. One is the watch phase. As my wife

likes to say, you watch for a warning, so the watch comes first. And, you know, when you're thinking about the warning, or sorry, watch, that's when you're using computer models to get an idea of the ingredients for severe thunderstorms and possibly tornadoes coming

together. And sometimes you can see that days in advance, all those ingredients coming together. You don't know exactly where, when, or how intense, but you know roughly that, you know, there's going to be a day and as you get closer you can kind of narrow that down to an area where you can issue a watch and say okay in the next six hours the ingredients have come together that we could see tornadic storms here and it's in that period that people can take proactive measures like making sure all of the doors and

windows are closed in the house that's really important to not let the wind in your house because that just makes it easier for the roof to come off you know to tie down any potential potential projectiles around the home and the property and make sure you have a safety plan. But then when the warning hits, this is based on radar. I mean, you're not using computer models at that point. You're just using the radar network. That's the number one tool across Canada for doing severe thunderstorm warnings. And in particular with tornadoes, you're looking for storms that themselves are rotating.

It's a different scale of rotation in the tornado, but the actual rotation of the storm, meaning it's very strong, very intense, very large updrafts that can support big tornadoes and large hail. You can actually see that in doplessar radar. And that's what they'll base a lot of the warnings on. Of course, if they get a call saying a tornado is happening, they'll issue a warning too. Okay, the second thing I want to pick up on from what you said earlier is this idea that, not idea, the fact that there are more warnings being issued. What's the danger of, you know, the boy who cried wolf?

words, if they don't happen, people might get complacent and say, well, I don't have to do anything. Sure. Well, I think that's a real consideration. I know the forecasters, having worked closely with them over the years, that's something they think about all the time when they're issuing warnings. But, you know, the literature says that, you know, when you look in closely into this issue, it's not as big of a deal as people think, that people, that people, feel more like, hey, someone's watching out for me rather than, hey, I'm getting way overwarned here. But there is a limit to that. And there's another aspect to this too in that Environment Canada's current warning areas,

the area that they, the minimum area that they can issue a warning for, sometimes they're really large. So you get parts of a large area that have the storm, but all of the warning goes to all those people in the area, including maybe a big city that's not affected at all. And so the plan is to really reduce the areas, make them kind of storm-scale polygons that they issue the warning for. So only the people affected by the storm really get the warning. That cuts down on the false alarms. That program, it's been in development for a number of years, and hopefully by next year

will be in place. They've had it in the U.S. for over a decade now. You mentioned the heat dome specific to what we're seeing this year. We know by some what of a comparison, that wildfires are increasing all the time because of climate change. How does climate change affect tornadoes? Will we be seeing more regardless if there's a specific heat dome in a summer? Right.

It's a really tough question because when you get down to the scale of tornadoes and thunderstorms, the connections between climate change and those kind of phenomena really get harder to define. But we know a few things. we know that the severe weather season is getting longer, starting earlier, ending later, going farther north because of the increased heat, and that just increases the chances that you're going to get severe thunderstorms.

But what's also happening is that with climate change, we're getting a reduced temperature difference between the poles and the equator. That reduces the strength of the jet stream. It becomes weaker, more wobbly, and weather systems that come across the continent, instead of just cruising along on the jet stream and passing through, get stuck.

They don't move for weeks at a time. And that's what's leading to a lot of our severe extreme weather. Like I said, the tornadoes over a period of three weeks, they just pile up and pile up because that pattern was stuck. The same with wildfires. You get all that heat, all that lack of precipitation. It just primes the atmosphere, the forest for wildfires. And then when they happen, you know, it basically all comes together in one big atmospheric mess, right?

You've got the combination of storms and smoke. And it's something that we're seeing more of each summer. And it's due to these patterns that are getting stalled as they cross. Dave, you know, you've told us, listen, friends, in Canada. Listen to me and others when we tell you there's a watch and a warning and do all the things. And yet you're the guy, one of these terms approaches when you have time,

that you go out and you chase these storms. Describe that experience for us just before we let you go. Sure. Yeah. I've seen two tornadoes so far this year, which is a bit unusual in southern Ontario. It's a lot easier to see tornadoes out in the prairies where you can see for, you know, kilometers

and kilometers. But storm chasing is something that, you know, people do for various reasons. Some people do it just for the thrill of it. That's not me. I'm out there trying to kind of connect what I've learned, all the textbooks, all the courses, you know, what I've seen over the years, with what I see on radar and satellite and that kind of thing, with what I can actually see as the storm happens. And once you put all of that together, it just makes a lot more sense, you know, when you can put out everything you've learned into action, nowhere to be

relative to the storm, know what to expect the storm to do. And, you know, there's a lot of challenge in it, too, because you have to forecast where to be. So, you know, tune up your forecasting skills to be in the right place. And then, you know, watching radar, knowing, knowing where to move to how the storm is going to behave. It's all really a challenge. It really is a way to appreciate nature, really. Like, just to see that force in front of you is really, you know, the true sense, the word, awesome. Better you than me, my friend. Better you than me. Appreciate your time, Dave. Thank you very much.

Oh, thanks for having me. Dave Sills is director of the Northern Tornadoes Project at the Canadian Severe Storms Lab at Western University in London, Ontario. This has been the current podcast. You can hear our show Monday to Friday on CBC Radio 1 at 8.30 a.m. At all time zones, or you can also listen online at cbc.ca.ca. Or on the CBC Listen app or wherever you get your podcasts. My name is Matt Galloway.

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