Tornadoes

Source: Environment Canada, 2017

• A tornado is a violently rotating column of air that extends from a cumuliform cloud to the surface. A tornado can be tens to hundreds of metres wide and have a lifespan of minutes or hours. In terms of size and area, it is one of the least extensive of all storms, but in terms of how violent storms can be, it is the world’s most severe. Winds can range from 90 to 315 km/h or greater. Canada has the second highest tornado occurrence rate in the world, behind the United States.
• What to look for:
  • A funnel cloud that extends fully or partially from the cloud to the surface.
  • Rotating debris near the ground or a spray near the water surface.
  • Sky may be an unusual green colour
  • Wind will sound like a freight train.
• What to listen for:
  • Tornado Watch: A watch issued by Environment Canada’s Meteorological Service when severe thunderstorms are forecast, and conditions are favourable for one or more tornadoes to be spawned from those thunderstorms within a defined ‘watch’ area.
  • Tornado Warning: A warning issued by Environment Canada’s Meteorological Service when at least one tornado is imminent, as indicated by observation, reports and/or radar scans.
  • Severe Thunderstorm Watch: Severe thunderstorms are possible in your area.
  • Severe Thunderstorm Warning: Severe thunderstorms are occurring.
• Note: Tornadoes occasionally develop in areas in which a severe thunderstorm watch or warning is in effect. Be vigilant to signs of an approaching tornado. Severe thunderstorm and tornado watches are often issued several hours in advance of thunderstorm developing. On the other hand, it may be a rapidly developing situation with less than an hour before the storms impact.
• This section includes a Sample Tornado Preparedness Guide.