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dangerous tornado approaching wind turbine

dangerous tornado approaching wind turbine (BeyondImages, iStockphoto)

STEM in Context

What is a Tornado?

Let's Talk Science
Format
Video Text Images
Readability
6.97
Subjects

Summary

Tornadoes are a common extreme weather phenomenon in Canada. How are they formed? How can you stay safe? And what is a storm chaser?
How do tornadoes form? (2014) by James Spann (TED Ed) (4:11 min.).

When you think of weather in Canada, what do you think of? In many provinces and territories, you might think of cold winters. In big inland cities, you might think of summer heat. If you live near an ocean, you might think of rain, drizzle and fog.

But did you know that Canada is one of the most tornado-prone countries in the world? An average of 62 tornadoes hit Canada every year!

Let’s look at how a tornado forms, and what parts of Canada are most likely to experience one.

How does a tornado form? 

According to Environment Canada, a tornado is a rotating column made up of high winds. You can recognize a tornado from its funnel-like shape.

 

Funnel-shaped tornado seen in the distance
Funnel-shaped tornado seen in the distance (Nikolas Noonan via Unsplash).

 

Usually, a tornado begins with an extremely large type of thunderstorm, called a supercell storm. However, for a tornado to form, some other very specific weather conditions are required. First, warm air has to rise toward the storm clouds. As this air rises, it gains speed, creating an updraft. As more air is swept into the updraft, it can change direction and gain speed. The updraft also carries moisture toward the clouds. The clouds can retain this moisture and use it later to fuel the tornado. 

If all of these conditions occur, a vortex (spinning air) forms within the storm. This vortex is called a mesocyclone, and it looks like a funnel-shaped cloud. Cool, dry air wraps around the mesocyclone, creating a downdraft. This results in a vast temperature difference between the inside and outside of the mesocyclone. The bottom portion of the mesocyclone will narrow, causing the winds to spin faster. From there, the mesocyclone sinks within the storm. If it reaches the moisture that was previously retained within the storm cloud, the moisture will become sucked into the funnel. This gives the mesocyclone the fuel it needs to become the massive rotating wall of clouds that we call a tornado!

Tornadoes can be very violent. This is due to their extremely high rotating wind speeds. The speed of the wind in a tornado can range from 180 km/h to 400 km/h. How fast is that? Well, on most highways in Canada, you can only drive 100 km/h. Tornadoes move a lot faster than that!

Where do tornadoes happen?

In Canada, tornadoes are often caused by warm air travelling up from the United States. There are two main areas of Canada that are most likely to experience tornadoes. One ranges from the Prairies in Alberta all the way to Lake Superior in Ontario. The other area covers southern Ontario and southern Quebec. Some scientists think that central British Columbia may also be tornado-prone. 

Map of all verified tornadoes in Canada between 1980 and 2009
Map of all verified tornadoes in Canada between 1980 and 2009, coloured by F-scale. From Sills, D. (Environment Canada) et. al (2012) (Environment Canada). Note: Canada now uses the Enhanced Fujita or EF scale.

In the United States, tornadoes are often caused by cold air travelling down from Canada. This happens in the Great Plains region, which covers North Texas, Oklahoma, Kansas and Nebraska. This area gets so many tornadoes that the media has nicknamed it Tornado Alley!

Did you know?

In Canada and the United States, tornado strength is measured using the Enhanced Fujita scale, or EF scale. It ranks tornadoes from 0 (little damage) to 5 (massive damage). 

 

Infographic - Text Version

Tornadoes range from EF-O which have speeds of 104 to 137 km/h and produce light damage to EF-5 which have speeds greater than 322 km/h and produce extreme damage.

 

Tornado damage shown using the Enhanced Fujita Scale
Tornado damage shown using the Enhanced Fujita Scale (Let’s Talk Science using data from the National Oceanic and Atmospheric Administration (NOAA) and an image by b44022101 via iStockphoto).

 

Graphic - Text Version

Tornadoes range from EF-O which have speeds of 104 to 137 km/h and produce light damage to EF-5 which have speeds greater than 322 km/h and produce extreme damage.

 

Most tornadoes last between 10 and 40 minutes. But they can cause enormous damage in that amount of time. They can flip cars over. They can destroy houses. They can even pull trees right out of the ground!

Did you know?

Canada’s most destructive tornado struck Regina, Saskatchewan in 1912. Dubbed the “Regina Cyclone”, it killed 28 people, injured another 300 and destroyed the homes of a quarter of the city’s residents!

How do you know if a tornado is coming? What should you do about it?

There are several ways to tell if a tornado is on its way. A funnel cloud is the most obvious sign. But severe thunderstorms, especially ones that darken the sky, could also be a warning. Sometimes you’ll hear a rumbling or whistling in the air before a tornado strikes.  

To know for sure, tune into your local radio station. You can also check with Environment Canada, the department responsible for monitoring weather and issuing tornado warnings. 

A storm chaser adjusts the rooftop weather station
A storm chaser adjusts the rooftop weather station on his chase vehicle as a severe storm builds in the background (BeyondImages via iStockphoto).

If you suspect that a tornado is coming your way, get inside. Get as far as you can from any windows—they may break!  Basements and ground-floor bathtubs are good places to wait out the storm.

What is a storm chaser?

Not everyone hides when a tornado is coming. People called storm chasers actually go out and try to get in a tornado’s path! Sounds like an adventure, doesn’t it? Storm chasers may love the thrill of the chase, but they also have bigger goals. They aim to eventually be able to predict when and where tornadoes will strike. To achieve this goal, they use special tools to measure tornadoes. 

Storm chasers are often the first to know when a tornado is on its way. They’re sometimes the first ones to inform Environment Canada and its American equivalent. They are also often on the scene to help out when tornadoes cause big trouble. 

Many storm chasers do it as a hobby. But some people make a living out of it.

Starting Points

Connecting and Relating
  • Have you ever experienced a tornado or been impacted indirectly by a tornado?
  • Do you think of Canada as a place that gets lots of tornadoes? Why or why not? 
  • What would you do if there was a weather alert of a tornado sighting in your area?
  • Does chasing storms sound like something you would like to do? Why or why not? 
Connecting and Relating
  • Have you ever experienced a tornado or been impacted indirectly by a tornado?
  • Do you think of Canada as a place that gets lots of tornadoes? Why or why not? 
  • What would you do if there was a weather alert of a tornado sighting in your area?
  • Does chasing storms sound like something you would like to do? Why or why not? 
Relating Science and Technology to Society and the Environment
  • Consider the societal and environmental impacts of a tornado, over the short term and the long term.
  • Should buildings constructed in areas that are prone to tornadoes be built to stronger standards than buildings in other areas?
Relating Science and Technology to Society and the Environment
  • Consider the societal and environmental impacts of a tornado, over the short term and the long term.
  • Should buildings constructed in areas that are prone to tornadoes be built to stronger standards than buildings in other areas?
Exploring Concepts
  • What conditions are necessary for a tornado to form? 
  • Where is Tornado Alley? Why is this area prone to tornadoes? 
  • Where are tornadoes most likely to form in Canada? 
  • How is the size of a tornado measured? 
Exploring Concepts
  • What conditions are necessary for a tornado to form? 
  • Where is Tornado Alley? Why is this area prone to tornadoes? 
  • Where are tornadoes most likely to form in Canada? 
  • How is the size of a tornado measured? 
Nature of Science/Nature of Technology
  • How are storm chasers connected with meteorologist in reporting tornado activity? 
Nature of Science/Nature of Technology
  • How are storm chasers connected with meteorologist in reporting tornado activity? 
Media Literacy
  • Is there a place for citizen scientists in reporting on weather conditions? What role do they play?
  • Have you ever submitted a photo of weather conditions to a television station or a weather website? What motivated you to do this? Do you appreciate photos and videos from others on these platforms? Why or why not? 
     
Media Literacy
  • Is there a place for citizen scientists in reporting on weather conditions? What role do they play?
  • Have you ever submitted a photo of weather conditions to a television station or a weather website? What motivated you to do this? Do you appreciate photos and videos from others on these platforms? Why or why not? 
     
Teaching Suggestions
  • This video and article can be used to support teaching and learning of Earth Science and Weather related to extreme weather, clouds and wind. Concepts introduced include tornado, supercell storm, updrafts, vortex, mesocyclone, downdraft and storm chasers. 
  • After reading this article and watching the video, teachers could have students complete a Print-Video Venn Diagram learning strategy to collect and compare the key information in both resources. Ready-to-use Print-Video Venn Diagram reproducibles for this video and article are available in [Google doc] and [PDF] formats. 
  • To consolidate learning, teachers could have students complete a Concept Definition Web learning strategy. Ready-to-use Concept Definition Web reproducibles for this video and article are available in [Google doc] and [PDF] formats. 
  • To go further, teachers could have students consider the value and impact of having timely and accurate reporting of tornadoes from the perspective of different people in society, using an Issues & Stakeholders learning strategy. Perspectives could include the general public, farmers, emergency response staff, hospital staff and public utilities.  Ready-to-use Issues & Stakeholders reproducibles for this article and video are available in [Google doc] and [PDF] formats.  
    • Issues & Stakeholders statement: It is important to have timely and accurate tracking and reporting of tornadoes. 
Teaching Suggestions
  • This video and article can be used to support teaching and learning of Earth Science and Weather related to extreme weather, clouds and wind. Concepts introduced include tornado, supercell storm, updrafts, vortex, mesocyclone, downdraft and storm chasers. 
  • After reading this article and watching the video, teachers could have students complete a Print-Video Venn Diagram learning strategy to collect and compare the key information in both resources. Ready-to-use Print-Video Venn Diagram reproducibles for this video and article are available in [Google doc] and [PDF] formats. 
  • To consolidate learning, teachers could have students complete a Concept Definition Web learning strategy. Ready-to-use Concept Definition Web reproducibles for this video and article are available in [Google doc] and [PDF] formats. 
  • To go further, teachers could have students consider the value and impact of having timely and accurate reporting of tornadoes from the perspective of different people in society, using an Issues & Stakeholders learning strategy. Perspectives could include the general public, farmers, emergency response staff, hospital staff and public utilities.  Ready-to-use Issues & Stakeholders reproducibles for this article and video are available in [Google doc] and [PDF] formats.  
    • Issues & Stakeholders statement: It is important to have timely and accurate tracking and reporting of tornadoes. 

Learn more

Tornado! How, When & Where Twisters Form (2011)

Infographic from Live Science containing tornado statistics, including information about how tornadoes form and the kinds of damage they cause. 

How do Tornadoes Form? (2014)

A TED-Ed Video (4:11 min.) explaining how tornadoes form and the role that storm chasers play. Note that this resource was also used as a reference.

References

Blackley, S. (2018, September 17). Are tornadoes in Canada on the rise? A look at the dangerous storms. The Globe and Mail.

Government of Canada. (2018, February 21). Tornadoes.

National Geographic. (n.d.). Tornadoes.

Stransky, S. (2014, October 16). How many tornadoes does Canada really get? AIR Worldwide.

Weather Wiz Kids. (2015). Tornadoes.