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This page documents the tornadoes and tornado outbreaks of 2011. Extremely destructive tornadoes form most frequently in the U.S., Bangladesh and Eastern India, but they can occur almost anywhere under the right conditions. Tornadoes also appear regularly in neighboring southern Canada during the Northern Hemisphere's summer season, and somewhat regularly in Europe, Asia, and Australia. There were 1,692 tornadoes confirmed in the U.S. in 2011. 2011 was an exceptionally destructive and deadly year for tornadoes; worldwide, at least 571 people perished due to tornadoes: 12 in Bangladesh, two in South Africa, one in New Zealand, one in the Philippines, one in Russia, one in Canada and 553 in the United States (compared to 564 U.S. deaths in the prior ten years combined).〔 Due mostly to several extremely large tornado outbreaks in the middle and end of April and in late May, the year finished well above average in almost every category, with six EF5 tornadoes and nearly enough total tornado reports to eclipse the mark of 1,817 tornadoes recorded in 2004, the current record year for total number of tornadoes. 553 confirmed fatalities is also the second-most tornadic deaths in a single year for tornadoes in US history, behind only 1925 in terms of fatalities attributed to tornadic activity. This total is due in large part to the 324 tornadic deaths that occurred during the 2011 Super Outbreak across the Southeastern United States and the 158 tornadic deaths in the 2011 Joplin tornado. ==Synopsis== An ongoing outbreak at the end of 2010 continued into the first three hours of 2011. During that period seven tornadoes touched down in Mississippi. However, during the remainder of the month, tornadic activity was suppressed by a cold air mass, with nine additional tornadoes – all weak – taking place.〔 This inactivity continued through much of February before a pattern shift. Two consecutive outbreaks took place on February 25 and 27 – 28, producing a combined 55 tornadoes. Overall, 63 tornadoes were confirmed in the month, ranking it as the fourth-busiest February on record. Activity in March was split between the start and end of the month, with a total of 75 tornadoes touching down, which ran slightly above average for the month. In early April, a prolific severe weather event produced at least 42 tornadoes among more than 1,200 reports of wind damage, setting the tone for the month.〔 A nearly continuous series of major tornado outbreaks followed thereafter in the remainder of April, including two extreme multi-day tornado outbreaks that were among the largest in U.S. history (one of them also one of the deadliest and the costliest) and two other large tornado outbreaks, and combined they resulted in an incredibly active month from start to finish; it was easily the most active month for tornadoes on record and by an extremely large margin the most active April, with over 765 tornadoes touching down. In an abrupt reversal, the activity did not continue into May (normally the most active month for tornadoes), however, and the first half was remarkably quiet and one of the least active Mays on record as of the middle of the month. That continued for three weeks until significant severe weather returned on May 21, and an extremely deadly tornado hit the following day in a major outbreak. The outbreak continued for the next several days, with over 180 confirmed touchdowns, bringing the month of May near average. The first day of June brought a rare outbreak into Massachusetts, where several tornadoes touched down, some of them fairly destructive. However, another reversal took place afterward and much of June was fairly quiet, with the exception of an active period in the third week that produced a moderate outbreak. July was also relatively quiet for the most part with below normal activity mostly clustered in the northern Plains. August was more quiet with below normal activity and only about 50 confirmed tornadoes. September and October were also below average. November was somewhat more active, primarily due to two moderate outbreaks in the first half of the month. December saw a return to inactivity for most of the month, but there was a small outbreak of 13 tornadoes on December 22 to close out the year. 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「tornadoes of 2011」の詳細全文を読む スポンサード リンク
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