The vulnerability of the small mediterranean village of Alcanar to floods: hasincreased the impact or the number of cases in the last years?

The Montsià county is the southernmost region of Catalonia (NE Spain), located between the final stretches of the Ebro River and the Sénia River. It is crossed by a relatively high mountain north-south oriented range (Serra del Montsià, 764 m.a.s.l). This range runs very close and parallel to the coastline. Numerous steep torrents originate in these mountains and traverse densely populated areas (particularly in the summer months). This affects mainly tourist and summer resorts, producing a heightened vulnerability to flooding. The municipality of Alcanar is a clear example of this situation. Between 1980 and 2020, Montsià County recorded 42 flood events, with 21 causing significant damage in Alcanar. These flooding events are typically triggered by very convective and high-intensity local and sudden rainfall, making accurate predictions challenging. The recent flood events of October 2018 and September 2021 and 2023 are good examples of such situations.

In this framework, our research seeks to fulfill two main objectives. The first one is to perform the meteorological analysis of the former three events  (2018, 2021 and 2023). This part has consisted of the characterization of the synoptic environment and the role of the mesoscale in the lightning and precipitation patterns. Data from radar, lightning detection systems, and rain gauges have helped to reach this point. The events display high variability in several factors such as the electrical activity, cloud vertical development, the affected regions, and the precipitation field. Hence, they represent a complex analysis that might lead to better understand processes that could affect most of the Mediterranean basin, as well as other regions around the globe. The second goal has been the characterization of the frequency and possible temporal trends of heavy rainfall events using daily and sub-daily precipitation data.