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 are many sources of uncertainty in the statistics mentioned on this page. Before the 20th century, and even until recently in third-world countries, records-keeping was spotty at best. Before the American Civil War, slave deaths were often not included in tornado death tolls. Fatalities of African-Americans in the Southern US were routinely not counted through the 1940s and in some cases into the 1950s. Most tornadoes from many decades ago had no official government report on damage or casualties, so statistics must be compiled from local newspapers, which are not always a reliable, consistent, or comprehensive source. Many death tolls were published with people still missing, or with people critically injured and likely to die later. News media, Red Cross, and other counts don't necessarily distinguish whether a death was directly caused by a tornado and can include deaths during cleanup efforts. Routine counting of fatalities began in the US in the 1950s. In Bangladesh and India, exact populations of towns were often not known, so most death figures are approximate. Individual tornado descriptions go into more detail on these uncertainties. Officials in some areas, for example in Russia (and the USSR) and parts of Europe, until recent years denied that tornadoes occur in those areas thus fatalities may not be counted as tornadic.