The tornado history of the Czech Lands, AD 1119-2010

Documentary evidence is employed to present the history of tornadoes in the Czech Lands (recently Czech Republic) in AD 1119-2010. Based on contemporaneous descriptions of events, tornadoes are categorised as proven or probable. They are analysed collectively in terms of their spatio-temporal changes, annual variation, specific features, and impacts according to the Enhanced Fujita (EF) scale. The first documented tornado, on 30 July 1119, did great damage to Vyšehrad Castle in Prague (EF3). Only three other tornadoes were recorded before AD 1500. In the following three centuries, the number fluctuated between 11 and 16 events per century. Documented tornado frequency increased significantly from the 19th century onwards, reaching peaks in 1931-1940 (44 tornadoes) and particularly in 2001-2010 (56 tornadoes); this rise, however, reflects the availability of relevant sources as well as increased social awareness and advances in communication technology. A total of 264 tornado days and 307 tornadoes were documented for the Czech Lands in 1119-2010. Although they are relatively homogeneously extended over the territory of the Czech Republic, tornadoes tend to occur more frequently at lower and medium altitudes. The highest frequency of tornadoes is recorded for the summer half-year (mainly from June to August), although they may develop between March and October. Probable tornadoes have also been recorded in the winter months. The strongest tornadoes in the Czech Lands may be classified as EF3, largely with significant damage to buildings and trees, but 13 related deaths have also been recorded. The paper presents not only a new chronology and climatology for Czech tornadoes but is also an important contribution to the study of tornadoes in Europe.

► The history of tornadoes in the Czech Lands in the past millennium is addressed. ► A total of 307 tornadoes and 264 tornado days are documented for AD 1119-2010. ► Tornadoes occur mainly in lower and medium positions and in summer. ► The strongest tornadoes in the Czech Lands, up to EF3 on the Enhanced Fujita scale, damage buildings and trees. ► Much of the documentation of tornado frequency depends on availability of sources.