It's tornado season in Alberta. Here's what you should know

It's been a fairly wet spring for Albertans, and although the moisture may be bringing area farmers some much-needed relief, it's also creating ideal conditions for tornadoes.

A tornado southeast of Sundre, Alta., roughly 90 kilometres north of Calgary in Mountain View County, flattened one home and seriously damage four others Thursday, RCMP said. 

One person suffered minor injuries, but no one was seriously hurt. 

In 2021, the province saw just three confirmed tornadoes because of drought conditions across much of Alberta. But more wet weather means 2022 will likely be a more active tornado season, with several sightings already reported this month.

Alberta Bureau Chief for the Weather Network Kyle Brittain likes to call the current humidity across the province "crop sweat."

All those happy barley, wheat and canola plants are releasing more moisture into the atmosphere.

"Of course, that's the fuel for these storms," he said in an interview with the Calgary Eyeopener.

"It looks like we're actually going to be ramping up in some severe weather."

The Northern Tornadoes Project (NTP) tracks tornado activity across the country, aiming to better detect, understand and mitigate the harms of tornadoes. 

The group has confirmed just one tornado in Alberta so far this year — an EF1 tornado June 6 near Enchant, Alta., but several others are currently under investigation and should be added to the database shortly, including several near Alliance, Alta. and Bergen, Alta. earlier this week.

Research meteorologist with the NTP Lesley Elliott says she expects to see more severe weather for the western prairies through July.

"They have the right concoction of ingredients necessary for these more intense, potentially dangerous storms to develop," she said.

So as peak tornado season continues, here are a few things you may be wondering about how these storms develop and what to do if one hits.

What is a tornado?

The Alberta government's website defines a tornado as a "violent rotating column of air extending between a thundercloud and the ground and can reach speeds of up to 400km/h in some cases."

It goes on to say most develop in the late afternoon and early evening.

Brittain has a more visual explanation.

"Basically, you need rotation near the ground, so a little swirl of air near the ground and then you need to stretch that in the vertical ... so like a convective updraft, a thundercloud.

"If you picture a figure skater pulling in their arms and they spin faster, they're reducing their axis of rotation. That's basically what's happening when you've got that strong lift above that rotating air near the ground, and it can spin it up to tornado strength … and get those winds to 90km/h or greater at the surface to be considered a tornado."

What is the peak season?

Typically, June through August, although the season can last longer. Basically, for Alberta, it all comes down to local precipitation.

"How much rain falls in June and July can really set up our season," Brittain says.

There's also wind shear, or changes in wind speed and direction, and more instability in the air this time of year, Elliott says. 

"We have a lot of surface heating. You can have warm air at the ground and some colder air aloft. So that kind of provides more energy for a parcel that's rising to have potential to become a strong updraft."

In the Prairies, conditions are ripe in the summer for some of the most concerning storms, Elliott says — supercells and organized squall lines. Tornadoes need a thunderstorm to act as a trigger. 

"If you see a vortex on a sunny day in a field with no cloud above it, you're looking at a dust devil ... Those tend to be very harmless."

Where is a tornado most likely to form in Alberta?

Along the Foothills and through central Alberta.

"It seems that most tornadoes would likely be co-located with where most of our thunderstorm activity is," Brittain says. 

"So basically right through the most populated sections of our province between Calgary and Edmonton from the Foothills pushing east."

The province's north does see its share, but they're likely underreported since those areas have smaller populations. 

How many tornadoes do we see in Alberta each year?

About 15. That number comes from climatology done by Environment and Climate Change Canada between 1980 and 2009.

Nationally, Canada sees about 61, although some suggest that estimate is low. For example, the NTP documented 72 tornadoes in 2019, 103 in 2020 and 100 in 2021. 

As of July 7, we're up to 19 confirmed across Canada, with several more under investigation.

One of the NTP's goals is to find the undocumented tornadoes in areas where people may not see them in order to provide a more accurate picture of how many there really are.

"So when a tornado goes through a forest, trees that fall will create a pattern that's pretty easily recognizable to us now when we compare before and after imagery, and we found that in certain crops at certain times in the growing season, we can see tornado tracks through farmers' fields as well now," says Elliott.

Are we seeing more tornadoes?

That remains to be seen, but it's an answer the NTP is working towards. Having only started as a pilot project in 2017, they need a longer stretch of data before coming to any conclusions.

Take last spring and summer in Calgary. The high temperatures and smoke resulting from the B.C. heat dome meant a suppression of the prairie storm season.

Alberta saw just three tornadoes in 2021, compared to 11 in 2020 and 23 in 2019.

So, no clear trends yet.

What should I do if a tornado is approaching?

Seek shelter immediately and try to find a room below ground, avoiding windows and protecting your head.

The Alberta government shares more tips on how to stay safe here.