The definition of a tornado is a violently rotating column of air, in contact with the ground surface, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often visible as a funnel cloud.
Environment Canada has confirmed that 15 of these violently rotating columns of the air have touched down in the province so far this summer.
On average the province records approximately 17 tornadoes each year. Environment Canada says Saskatchewan is prone to more tornadoes each year than any other province in Canada – the question is why?
“It is a hotspot for tornadoes, we’re sort of the extension of the Tornado Alley that goes through the United States, we are on the northern extent,” says Environment Canada Meteorologist, Terri Lang.
Tornadoes can be formed from a number of storm types which include supercells, bow echoes and squall lines, pulse storms, and many more. Tornadoes need certain elements such as heat, moisture, wind, and trigger to come together to form a tornado.
“Heat is definitely one of the ingredients. When the heat starts to breakdown that’s when we get the storms and that’s when we tend to get the tornadoes.”
“The other thing we need is moisture, and this year we happen to have an abundance of moisture. One of the biggest contributing factors to moisture in the atmosphere is growing crops. We’re at peak growing time right now with the crops and they’re giving off tremendous amounts of moisture, it’s called evapotranspiration.”
Another element needed to form a tornado is winds in the upper atmospheres to be changing, which Saskatchewan has in spades.
“That allows the clouds to rotate, and when that happens the storms can get themselves more organized, and when the storms get more organized that’s when they’re more capable of producing tornadoes.”
The last thing needed for a tornado to form is a trigger – something to set things off.
“A cold front, an upper cold front, a trough, a dry line, something like that, that comes along to kick things off. Sometimes rain or lake breezes can do that, but those are the things that we need to set off the thunderstorms that are capable of producing tornadoes.”
If enough speed is created, tornadoes can create a lot of force that can do some serious damage. Data provided by Environment Canada says that tornadoes can generate wind speeds anywhere from 90-315 km/h, which can travel on average between 50 m and 100 plus kilometres.
With that generation of force comes severe damage to property, which is how tornadoes are measured by the Enhanced Fujita Scale (EF).
“They are rated based on the damage that they do. If we see a big tornado in a field and it doesn’t do any damage, we can’t give it a rating, because it doesn't do any damage. It had to hit something to be given a rating.”
In Canada, tornadoes are rated from EF0 with winds of 40-72 mph and light damage, all the way up to EF5 which has wind speeds ranging from 261-318 mph and creates catastrophic damage. Lang notes that the EF scale is used to rate a number of different types of winds.
Click here to see more...