Tornado climatology
Tornadoes have been recorded on all continents except Antarctica and are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as well as the strongest and most violent tornadoes. A large portion of these tornadoes form in an area of the central United States popularly known as Tornado Alley. Other areas of the world that have frequent tornadoes include significant portions of Europe, South Africa, Philippines, Bangladesh, parts of Argentina, Uruguay, and southern and southeast Brazil, northern Mexico, New Zealand, and far eastern Asia.
Tornadoes of 2011
There were 1,697 tornadoes confirmed in the United States in 2011. It was the second most active year on record, with only 2004 having more confirmed tornadoes. 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.