Revisiting a 24-year database of tornado damage paths using the new International Fujita (IF) scale

Tornadoes are the meteorological phenomenon capable of producing the most intense surface winds in the Earth, sometimes exceeding 100 m s-1. Tornado wind speed can rarely be measured in-situ using anemometers and radar. Nevertheless, it can be estimated through an analysis of the observed damage, especially when performing in-situ damage surveys (Rodríguez et al., 2020). The Fujita (F) scale (Fujita, 1971), which relates damage on buildings and forest with wind speed, was proposed with the aim of assessing tornado intensity. In the early 2000s was revised by the Texas Tech University proposing the Enhanced Fujita (EF) scale (WSEC, 2006). Both F and EF scales are broadly used, although it is hampering to apply them out of the USA because most damage indicators are related to typical building structures of that country, which are significantly different from those which are common in other regions.Recently, it has been proposed the International Fujita (IF) scale, which has been developed by several contributors from European universities and meteorological services coordinated by the European Severe Storm Laboratory (ESSL, 2023). IF scale considers a large variety of constructive structures and its sturdiness. This allows carrying out a detailed wind speed estimation based on damage surveys.In this work we revisit the 122 tornadoes included in the Catalonia tornado database 2000-2023 (NE Iberian Peninsula) with the aim of classifying events according to the new IF scale. We analyse and discuss spatial and temporally the results. Moreover, we compare them with previous classifications performed using F and EF scales, which showed that 92% of tornadoes reported in the region were weak (EF0 or EF1), whereas 8% were significant (EF2 or stronger) (Rodríguez et al., 2021). This study is partly supported by project PID2021-124253OB-I00. ReferencesESSL, 2023. The International Fujita (IF) Scale for tornado and wind damage assessments. European Severe Storm Laboratory, Wessling, Germany. https://www.essl.org/cms/wp-content/uploads/IF-scale_v1.0d.pdfFujita T.T., 1971. Proposed characterization of tornadoes and hurricanes by area and intensity. SMRP Research Paper, 91: 48.Rodríguez O., Bech J., Soriano J.D., Gutiérrez D., Castán S., 2020. A methodology to conduct wind damage field surveys for high-impact weather events of convective origin. Nat. Hazards Earth Syst. Sci., 20 (5): 1513-1531. https://doi.org/10.5194/nhess-20-1513-2020Rodríguez O., Bech J., Arús J., Castán S., Figuerola F., Rigo T., 2021. An overview of tornado and waterspout events in Catalonia (2000–2019). Atmos. Res., 250: 105415, https://doi.org/10.1016/j.atmosres.2020.105415WSEC, 2006. A Recommendation for an Enhanced Fujita Scale (EF-scale). Wind Science and Engineering Center (Texas Tech University), Lubbock, Texas, USA. https://www.depts.ttu.edu/nwi/Pubs/EnhancedFujitaScale/EFScale.pdf