List of Canadian tornadoes and tornado outbreaks

This page lists tornadoes and tornado outbreaks which have touched down in Canada prior to the 21st century. On average, there are around 80 confirmed and unconfirmed tornadoes that touch down in Canada each year, with most occurring in Southern Ontario, the southern Canadian Prairies and southern Quebec. Canada ranks as the second country in the world with the most tornadoes per year, after the US. The most common types are F0 to F2 in damage intensity level and usually result in minor structural damage to barns, wood fences, roof shingles, chimneys, uprooted or snapped tree limbs and downed power lines. Fewer than 5% of tornadoes in Canada are rated F3 or higher in intensity, where wind speeds are in excess of 225 km/h (140 mph). Prior to April 1, 2013, Canada used a slightly modified Fujita scale, and as of that date the Enhanced Fujita scale, again slightly modified, was put into use to rate tornado intensity, based on the damage to buildings and vegetation.

Ontario, Alberta, Manitoba and Saskatchewan all average 15 tornadoes per season, followed by Quebec with fewer than 10. New Brunswick and the British Columbia Interior are also recognized tornado zones. All other provinces and territories have significantly less threat from tornadoes. The peak season in Canada is in the summer months when clashing air masses move north, as opposed to the spring season in the United States southern-central plains, although tornadoes in Canada have occurred in spring, fall and very rarely winter.

The reported increase in numbers of tornadoes in recent years may reflect more reporting by citizens and media involvement rather than an actual increase in tornado occurrence (although some natural increase has not been ruled out), in addition to better detection technology i.e. Doppler weather radar and satellite imagery. The upswing could also be attributed to other factors, such as improved aerial and ground damage assessment after the fact in sparsely populated areas (particularly the case in remote parts of the Canadian Prairies and Northern Ontario, for example), better trained spotter capabilities and increased use of digital recording devices by citizens. Tornadoes in Canada are enough of a threat for a public warning system to be in place, overseen by the national weather agency, Environment Canada (EC).

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