Analysis of the sea storm of 23 rd -24 th October 2017 offshore Bari (Italy) Letizia Lusito, 1  Antonio Francone, 2 Davide Strafella, 1 Elisa Leone, 1 Felice D’Alessandro, 3 Alessandra Saponieri, 1 Samuele De Bartolo, 1 and Giuseppe Roberto Tomasicchio 1 1 University of Salento, Lecce (LE), Italy 2 Polytechnic of Bari, Bari, Italy 3 University of Milan, Milan (MI), Italy  Corresponding author: letizia.lusito@unisalento.it Between the evening of October 23 rd and the evening of October 24 th 2017, a sea storm hit the city of Bari, along the Adriatic coast, in the south of Italy, causing widespread damages. Due to the absence of direct observations of wave characteristics, the present paper is aimed to (i) compare the development of the occurred sea storm as hindcasted by ’84 method with the predictions by atmos- phere-ocean numerical models and satellite observations and (ii) estimate the most reliable value of the significant wave height, H s , at the peak of the sea storm, with its associated return period. As a result, the ’84 showed the better agreement with the satellite observations in determining the value of H s at the peak of the sea storm, compared with the predictions by more sophisticated atmosphere- ocean numerical models. In particular, the obtained value of H s , equal to 6.58 m, makes the investi- gated sea storm an exceptional event. Keywords: wind forecast, waves forecast Introduction On the 23 rd and 24 th October 2017, an unstable air front on the central-southern Adriatic Sea caused a storm of intensity 8/9, according to the Beaufort scale, coming from the northern quadrants (AM, 2017) and consequent very rough sea. The storm hit the coast of the city of Bari from the evening of 23 rd till the evening of 24 th October 2017. Figure 1 shows the geographical position of Bari (a) and the action of the wave agitation along the stretch of coast north of the commercial port of Bari on the morning of 24 th October 2017 (b). The storm caused considerable damages to the infrastructures under construction on the coast north of the com- mercial port, as shown in Figure 2, in particular, on the waterfront “IX Maggio”, whose geographical position is highlighted in Figure 3. Unfortunately, there was no direct measure- ment of the significant wave height, H s ; as a con- sequence, the values of H s during the sea storm have been determined on the basis of wind data from direct observations and hindcasted values. The aim of the present study is to determine the values of H s , occurred during the storm, and to obtain the related return period. The analysis has been conducted with different methodologies. H s values from wave hindcasting 445 Aquatic Ecosystem Health & Management, 23(4):445–452, 2020. Copyright # 2020 AEHMS. ISSN: 1463-4988 print / 1539-4077 online DOI: 10.1080/14634988.2020.1807303 Downloaded from http://scholarlypublishingcollective.org/msup/aehm/article-pdf/23/4/445/1452383/445lusito.pdf by guest on 05 February 2022