Calgary (Rural Roots Canada) – A series of tornado warnings in east-central Alberta last week serves as a reminder that it’s that time of year again.

RRC Meteorologist David Spence says we are just starting the time of the year when conditions for tornadoes happen.

“Usually, the season goes from about May to September, but the core of the season is usually between June and the first two weeks of August,” says Spence.

He adds that the season ramps up in June, and once you pass the first two weeks of August, the tornado risk dramatically falls off.

Spence says, to his knowledge, there has been one tornado in Alberta so far this year, which happened in April just east of Airdrie.

That tornado was a landspout and was very small.

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Signs to Watch For

Spence says there are a number of factors you should keep your eye on when you are looking up at the sky.

He says you won’t get any tornado warnings in those early morning weather reports. They typically occur five to 15 minutes before the event.

“What you can watch for, keep an eye on the western sky and watch for towering clouds, the big puffy white clouds that go high into the sky, towering cumulus clouds.”

If those start to develop on the Western horizon by about noon or two o’clock in that two-hour window, then you’ve got a pretty good chance that some severe weather may develop later on in the day.

Spence says it depends on where you are and how close you are to the clouds when they form.

He says these storms can pack a wide range of weather, including hail, strong wind, intense rainfall, and tornadoes.

“I mean, these kinds of clouds produce a wide variety of weather, almost none of it good because we like rain, but we like gentle rain. We don’t like cascading deluge of precipitation, which is what these storms often produce.”

He says if you’re in Saskatchewan or Manitoba, you’re going to see a different formation, but you are keeping a lookout for the same towering cumulus cloud off in the western horizons.

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How a Tornado Forms

Tornadoes are really small low-pressure systems, making them very powerful.

There are two ways a tornado forms, landspout and mesocyclone.

The landspout tornado starts out as a rotating column of air, usually horizontal, parallel to the ground. Then heat lifts it up into the vertical, becoming a vertical column of rotating air and debris spinning up from the ground into the sky. It’s like a Dust Devil on steroids.

Dust devils are very similar, but they’re not tornadoes. Landspouts are tornadoes because they rise high enough into the sky to reach a cloud above, a thundercloud, for example. Spence says the cloud itself may not be rotating, so it’s not a regular type of tornado that descends from a rotating cloud. It’s one that goes up from the ground and reaches a cloud; once it reaches the cloud, it’s officially considered to be a tornado. Those are usually EF0 and EF1 tornadoes, which are relatively low on the damage scale, and those are quite common in Alberta. We get about 12 to 15 tornadoes per year on average in Alberta, and by far, most of them are EF0 to EF1s, and among those, most of them are landspouts.

Mesocyclone tornadoes, which are the most dangerous kind, are by far the most dangerous kind.

While they range from EF0 to EF5, we’ve only had one EF5 ever in Canada, that was in Eli, Manitoba, several years ago.

Last year’s EF4 in Didsbury is still fresh in the minds of many, as it damaged several homes.

He adds if one does occur the safest place to be is in your house in the basement.


Spence says if Environment and Climate Change Canada has a warning, you need to go to the centre of the house and as low as possible, which means the basement.

“Put as many walls between you and the outside as you can, and that’s probably the best way to stay safe in a wind event, certainly a tornado event.”

He adds tornadoes are not the only weather events that people need to take precautions for.

“We have strong straight-line winds events as well. It can be quite destructive, and you want to keep yourself safe from those.”

Spence says it is imperative everyone get inside the house, as there could be a lot of debris flying around the farmyard.

He also says a barn is typically not a safe place to be when a tornado or major straight wind event happens.



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