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This page lists tornadoes and tornado outbreaks which have touched down in Canada. 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 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 250 km/h. As in the US, the Enhanced Fujita Scale is used 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 interior of British Columbia 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. For a variety of reasons, such as Canada's lower population density and generally stronger housing construction due to the colder climate, Canadian tornadoes have historically caused far fewer fatalities than tornadoes in the United States. The deadliest tornado in Canadian history, the Regina Cyclone of June 30, 1912, does not even rank in the top 25 when compared to American tornado fatalities. Urban centres are not immune from the threat of severe tornadoes. Nine medium to large size Canadian cities have been hit by significant strength tornadoes (F3 or higher), which caused large-scale damage and fatalities: Regina, Saskatchewan (1912); Windsor, Ontario (1946 and 1974); Sarnia, Ontario (1953); Sudbury, Ontario (1970); Woodstock, Ontario (1979); London, Ontario (1984); Barrie, Ontario (1985); Edmonton, Alberta (1987); and Goderich, Ontario (2011). == Before 1880 == 1792 * June 30, The first recorded tornado in Canadian history affected the Niagara Peninsula between Fonthill and Port Robinson, Ontario. It leveled houses and uprooted many trees. In fact, the tornado cut a path of trees in a west to east line from Fonthill to Port Robinson that became a road known as "Hurricane Rd", which still exists today.〔(The Weather Doctor's Diary: June - 30 June 1792, Niagara Peninsula, Ontario )〕 1829 * April 18, An area between Collingwood and Niagara-on-the-Lake, Ontario, were affected by tornadoes, one of which lifted a saloon up into the air. * June 2, The early settlement of Guelph, Ontario is destroyed by a strong tornado. Re-settlement does not begin for a few years afterwards. * August 7, First known and confirmed tornado death in Canada happened in Galt, Ontario, which is now Cambridge. 1860 * May 19, Homes, fences and trees were demolished by a 500 m wide tornado near Aurora, Ontario. Hailstones up to 8 cm in diameter also fell. 1870 * July 16, A tornado touched down in Montreal, Quebec. It only lasted 5 minutes and destroyed everything in its path. There was 1 unconfirmed death.〔(The New York Times - "Tornados" Published July 17, 1870 )〕 1879 * August 6, A suspected F3 tornado touched down near Bouctouche, New Brunswick. The twister killed 5 people, injured 10 and left 25 families homeless. It is considered to be the easternmost ''major'' tornado in North America. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「List of Canadian tornadoes and tornado outbreaks」の詳細全文を読む スポンサード リンク
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