| 翻訳と辞書 |
| 2011 Goderich, Ontario tornado ： ウィキペディア英語版 |
2011 Goderich, Ontario tornado
The 2011 Goderich, Ontario tornado (rated as an F3 on the Fujita Scale) was caused by an isolated supercell which unexpectedly tore across Huron County, Ontario, on the afternoon of Sunday, August 21, 2011. Beginning as a tornadic waterspout over Lake Huron, the tornado ripped through the lakeside town of Goderich severely damaging the historic downtown and homes in the surrounding area. One person died and 37 more were injured as a result. This was the strongest tornado to hit Ontario in over fifteen years, since the April 20, 1996, tornado outbreak in Williamsford, Arthur, and Violet Hill.〔(F3 tornado aftermath in Goderich "like a war zone" (The Weather Network) )〕
==Antecedent conditions==
There was little hint of what was to come that day as far as severe weather was concerned. Both Environment Canada in Toronto and the Storm Prediction Center in Oklahoma outlined the risk for non-severe thunderstorms that day across the lower Great Lakes.〔(Storm Prediction Center Outlooks for August 21, 2011 )〕 Lapse rates yielded limited instability for severe weather, with a secondary cold front acting as a trigger. Given the much colder air aloft (freezing levels near 700 hPa) coupled with surface heating there was the risk for small hail and gusty outflow winds, which was also mentioned. Though some upper-level wind field parameters were sufficient for tornadic activity, they were marginal at best when coupled with the synoptic pattern at hand (a highly atypical pattern compared to previous major tornado events in the lower Great Lakes region).〔(The Meteorology Behind the August 21, 2011 Goderich, ON Tornado )〕 Goderich is also located in the "lake shadow" of Lake Huron, which is much less likely to be hit by tornadoes than other parts of Southwestern Ontario where lake convergence fronts collide.〔http://www.yorku.ca/pat/research/dsills/papers/GLOMW2012/Sills_GLOMW2012.pdf〕
By 11:00am that morning, showers and thunderstorms began to develop over southwestern Ontario. Initially they were weak, but began to intensify in some localized areas. Hail and heavy rain came down with a line of storms tracking from northwest of Kitchener toward the Brampton area early that afternoon. There were reports of localized flooding and marginally damaging wind gusts associated with these storms. A brief tornado was also reported in Gananoque at 12:45pm. Later confirmed as an F1, this tornado caused minor damage in an area 1.5 kilometres long and 60 metres wide.〔(Tallying Canada's confirmed tornadoes (The Weather Network) )〕 Environment Canada issued a severe thunderstorm watch for most of southern Ontario as a result. The town of Goderich and surrounding areas of Huron County were included.〔(Special Weather Statements for Ontario )〕
At around the same time, an intense thunderstorm had developed over northern Michigan in Alcona County. Hail of up to two inches in diameter was reported to the National Weather Service and a velocity couplet appeared on Doppler weather radar at around 1:30pm.〔(Storm Prediction Center Reports for August 21, 2011 )〕 A tornado warning was subsequently issued, but the storm moved out over the relatively warm waters of Lake Huron shortly after. It weakened for a time, but began to intensify once again as it crossed the border into Canada by 3:00pm. Strong rotation began to develop on the southwest side of this thunderstorm as resolved by velocity images on the Exeter, Ontario radar, and a textbook-style hook echo soon appeared on reflectivity images too (see image to left). With the powerful storm closing in on Goderich from the northwest at approximately 75 km/h, Environment Canada issued a tornado warning at 3:48pm. The meteorologists estimated the storm would make landfall there in approximately ten minutes.
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「2011 Goderich, Ontario tornado」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|