|A spectacular image of the only EF-5 tornado (winds in excess of 320 km/h) ever recorded in Canada. The storm struck near Elie, Manitoba on the afternoon of July 22, 2007. (The Weather Network)|
|The deadly July 31, 1987 tornado that struck Edmonton, Alberta was a powerful EF-4 storm that killed 27 people, injured 300 and destroyed 300 homes.|
WATCH VS WARNINGS
Environment Canada with the use of Doppler Radar, provides advance watches and warnings when tornadoes are possible. It is important as we head into the summer season for Canadians to understand the terminology they use when posting warnings. A severe thunderstorm watch occurs when conditions are favorable for severe thunderstorms. It is just a watch, so go about your daily routine but keep and eye to the sky or your Smart phone with an app from The Weather Network or other weather provider. If thunderstorms develop on radar and become severe with strong winds (over 90km/h), heavy flooding rains or hail (greater than 2cm in diameter) a severe thunderstorm warning will be issued. Warnings are typically issued for a large geographic region, but the storm may only affect a portion of that region. Be vigilant just the same. Remember to seek shelter when storms occur as lightning remains one of the deadliest components of thunderstorms in Canada. I will talk more about lightning safety in a future post.
If weather conditions become more favorable for stronger storms with rotation, a tornado watch will be posted. They are rare in Canada but do occur. The watch will be for a larger area. If a warning is required it means you should find shelter immediately. A tornado warning will be issued, typically for a more precise area, if a tornado is observed on the ground or detected on radar. Tornadoes typically are short lived in Canada and cover a very narrow path. They are extremely violent with intense winds and very low pressure. You must seek shelter indoors and at the lowest level of the dwelling, away from any windows or doors. If outside find the lowest place to lie flat and cover your head. Many people think a highway underpass is a safe alternative in a tornado, they are not.
Please remember that if any day this summer looks particularly dangerous for strong thunderstorms, I will post an update in advance as well as post any watches or warnings via my twitter feed during the severe weather. Most weather apps have features now that will notify you when watches or warning shave been posted for your region.