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.
List of F5 and EF5 tornadoes
In all, 63 tornadoes have been officially rated F5/EF5 since 1950: 59 in the United States and one each in Italy, France, Russia, and Canada. The works of Grazulis also revealed 16 more F5 tornadoes between 1950 and 1995, with four later being accepted by the NCDC. Since the implementation of the Enhanced Fujita scale on February 1, 2007, there have been nine officially rated EF5 tornadoes in the United States from May 4th, 2007-May 20th, 2013 to date, while previously fifty tornadoes were officially rated F5 on the original Fujita scale from May 11th, 1953-May 3rd, 1999.