Although predicting the occurrence and intensity of severe convective storms is improving, the impacts of severe convective storms – hail, convective wind gusts, tornadoes, heavy rain, and lightning – cannot be explicitly forecast within global or mesoscale models. Spatial and temporal distributions, or climatologies, of severe weather events can be used to understand convective storms and their impacts in Europe as well as their variability and can also serve as a baseline for understanding the possible influence of climate change. What we know so far about the impact of severe storms in Europe? In this post I try to answer this question. I will focus only on the impact of tornadoes* because tornadoes are low probability high impact events, and also because the general view is that tornadoes have a very low impact in Europe compared with the United States.
There are different ways to assess the impact of tornadoes, for example based on damage estimations. Unfortunately different damage estimation methodologies are used across Europe and also is very difficult to estimate the damages for historical events. An alternative would be to use the number of tornado fatalities which is more representative for both historical and recent events and also for different countries.
The figure bellow shows the spatial and temporal distribution of tornado fatalities between 1091–2013 based on data from the European Severe Weather Database, published tornado climatologies, personal communications from Dr. Rudolf Brázdila (Czech Republic), Mateusz Taszarek (Poland), Dr. Petio Simeonov (Bulgaria), Stavros Dafis (Greece), Abdullah Kahraman (Turkey), and my own research. In the figure, I have also indicated (around the edges of the map) the highest impact event (based on the number of fatalities) for each European country for which tornado reports were available.
The spatial and temporal distribution of deadly European tornadoes based on data from 1091 to 2013. The number of fatalities is represented by varying the size of the circles, and the period by changing the colour. (click on the image to explore the details).
The earliest deadly European tornado hit central London on 23 October 1091 (Rowe 1999). The event was described by Britton (1937) as a "great gale", but the description by Florence of Worcester indicates a tornado.
“A very powerful whirlwind, coming from the south, knocked down more than 600 houses and a considerable number of churches. It also struck the church called St. Mary le Bow, killed two people in it and, lifting the roof with the timbers aloft, carried them back and forth in the air for a long time. Finally it fixed six of the timbers, in the same position in which they had been fixed in the roof, so deep in the ground that only a seventh of eight part [1.2 m] protruded; yet they were 27 or 28 feet [8.2–8.5 m] long”
A total number of 229 deadly tornadoes occurred between 1091 and 2013 and the majority, 82.5% of all cases, were associated with 1–5 fatalities. Five tornadoes (described bellow) resulted in more than 50 fatalities and all them occurred (with one exception, the Ivanovo tornado from 1984) before the 20th century.
i. The Grand Harbour (Malta) tornado of 23 September 1551 (or 1555–1556). The Grand Harbour was hit by a waterspout that moved inland. At least four galleys, Santa Fè, San Michele, San Filippo and San Claudio that where prepared to go into battle, were destroyed by the waterspout resulting in at least 600 fatalities. (I was enable to find the sources describing this event. I have found a description of this case on the Tornado and Storm Research Organisation (TORRO) webpage, and also the event is included on the list of European tornadoes and tornado outbreaks. If you have more informations about this event I would be very interested to hear from you).
ii. The Cádiz (Spain) tornado of March 1671. The tornado occurred during the night between 0330–0400 am. Gayà (2011) indicated that
“the path fallowed by the phenomena, the places that it left unharmed, and the direction of the fall of the affected walls and other architectural elements all show that was a real tornado”
The tornado, classified by Sánchez-Laulhé (2005) as an F3, was associated with more than 600 fatalities according to contemporary accounts (Sena y Lara 1671, Gernonimo de la Conception 1690 cited by Gayà 2011); but other sources indicated this number as 1000 or 1500 fatalities (Ciprian Guillermo 1671 cited by Gayà 2011). If these estimations are correct, then the Cádiz tornado is one of
“world’s most important killer tornadoes, where most of the people died not trough the structural collapse of their homes, but through the capsizing of ships and smaller craft”
In the 17th century, Cádiz was one of the main European ports involved in the trade between America and Europe and many vessels from France, the Netherlands, Republic of Genoa, and England were damaged by the tornado (Gayà 2011).
iii. The Montville (France) tornado of 19 August 1845. At least 70 people were killed and 136 were injuries by the tornado that destroyed homes and three textile and paper mills near Montville. Most of the victims worked in a mill that collapsed during the event. Flammarion (1872) gives an account of this event
“Workers were hurled outside over hedges and fences...At other places, the buildings were as if pulverized and the place was completely cleaned. Joists, planks...were lifted up and carried away as far 25 of 38 km! Almost to Dieppe [approximately 40 km].”
Dessens and Snow (1989) had classified the tornado as an F5. The path of the tornado was 24 km long and up to 300 m wide (Grazulis 2001). (The French author Gustave Flaubert mention the Montville tornado in his letter to Louise Colet from 26 August 1845).
iv. The Sicily tornadoes of December 1851. Two large tornadoes swept the Sicilian plains moving northeastward from Marsala to Castellamare del Golfo. The total number of victims is unknown, but was estimated at over 500. An article published in the Illustrated London News (20 December 1851) describe the event
“Intelligence was received at Lloyd’s, under date Malta, Monday, the 8th instant, of a most awful occurrence at the island of Sicily, which had been swept by two enormous waterspouts accompanied by a terrific hurricane. Those who witnessed the phenomena describe the waterspout as two immense spherical bodies of water reaching from the cloud, their cones nearly touching the earth, and, as fas as could be judged, at a quarter of a mule apart, travelling with immense velocity. They passed over the island near Marsala. In their progress houses were unroofed, trees uprooted, men and women, horses, cattle, and sheep were raised up, drawn into their vortex, and borne on to destruction; during their passage rain descended in cataracts, accompanied with hailstones of enormous size and masses of ice. Going over Castellamare, near Stabia, it destroyed half the town, and washed 200 of the inhabitants into the sea, who all perished. Upwards of 500 persons have been destroyed by this terrible visitation, and an immense amount of property, the country being laid waste for miles. The vessels in the harbour suffered severely, many vessels being destroyed, and their crews drowned. After the occurrence number of dead human bodies were picked up, all frightful mutilated and swollen.”
v. Russian tornado Outbreak of 9 June 1984. This was probably Russia's deadliest tornado outbreak in history. At least eight tornadoes struck the Ivanovo and Yaroslavl region north of Moscow, killing at least 69 people in Ivanovo. Different sources (Süddeutsche Zeitung 1984, Peterson 2000) estimated a death toll of 400, but is not clear whether this number represent the number of victims for the Ivanovo tornado or for all tornadoes on 9 June (Finch and Bikos 2012). Finch and Bikos (2012), who examined the synoptic and mesoscale environments of this case, indicated that the outbreak contained one of the two F4 tornadoes reported in Russia (the other being the Moscow tornado of 29 June 1904).
Despite the common view that tornadoes in Europe have a low impact, the above examples show that high impact events can occurs in Europe. Based on the data from 2004–2013, on average five people are killed each year in Europe by tornadoes. In a recent paper, Groenemeijer and Kühne (2014) estimated (by multiplying the occurrence frequency with the average number of tornado fatalities per tornado per F-scale class) that the average annual number of tornado fatalities in Europe is between 10 and 15 (F2 and F3 tornadoes are responsible for the majority of the fatalities.)
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*) Here we adopt the definition from Rauhala et al. (2012) were "a tornado is a vortex between a cloud and the land or water surface, inwhich the connection between the cloud and surface is visible, or the vortex is strong enough to cause at least F0 damage."
Reference
Britton, C. E., 1937: A Meteorological Chronology to A.D. 1450. Geophysical Memoirs, 8, no. 70.
Dessens, J. and J. T. Snow, 1989: Tornadoes in France. Wea. Forecasting, 4, 110–132.
Finch, J., and D. Bikos, 2012: Russian tornado outbreak of 9 June 1984. Electronic J. Severe Storms
Meteor., 7 (4), 1–28.
Flammarion, C., 1872: L'atmosphère: description des grands phénomènes de la nature. Librarie Hachette, p. 888.
Gayà, M., 2011: Tornadoes and severe storms in Spain. Atmos. Res., 100, 334 - 343.
Grazulis, T. P., 2001: The Tornado: Nature's ultimate windstorm. University of Oklahoma Press, p. 352.
Groenemeijer, P. and T. Kühne, 2014: A climatology of tornadoes in Europe: Results from the European Severe Weather Database. Mon. Wea. Rev., in press.
Peterson, R.E., 2000: Tornadoes of the former Soviet Union. Preprints, 20th Conf. on Severe Local Storms, Orlando, FL, Amer. Meteor. Soc., 138–141.
Rauhala, J., H. E. Brooks, and D. M. Schultz, 2012: Tornado Climatology of Finland. Mon. Wea. Rev., 140, 1446–1456.
Rowe, M, 1999: "Work of the devil": Tornadoes in the British Isles to 1660. Journal of Meteorology, 24, 326--338.
Sánchez-Laulhé, J. M., 2005: El tornado de Cádiz de 1671. Boletín Asociación Meteorológica Española AME (2005), 9, 11–15 (in Spanish).
Sena y Lara, J., 1671: Relacion verdadera de los daños que en la civdad de Cadiz, y su bahia, causó el huracán y contrastes de viento, que sobrevino el Domingo de Laçaro (1671) 15 de Março, año de 1671. Printed by Iuan Vejerano, Cádiz 1671 (in old Spanish).