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 tornadoes causing 100 or more deaths
There is also meteorological uncertainty with the nature of many tornadoes on this list. Before the 1970s, and even now outside of North America, most tornado paths were not thoroughly surveyed to ensure that the storm was indeed a single tornado and not a series of tornadoes from the same storm (a tornado family). Often a single supercell can produce a new tornado soon after or even before the demise of an old tornado, giving the appearance to many observers that a single tornado has caused all the damage. On this list, if it is likely that the tornado was in fact two or more tornadoes, it will appear in "italics".