The coastline of the Gulf of Naples, Italy, is characterized by a series of infrastructures of strategic importance, including touristic and commercial ports between Pozzuoli to Sorrento, main roads, railways, and urban areas. Furthermore, the Gulf of Naples hosts an intense traffic of touristic and commercial maritime routes. The risk associated with extreme marine events is hence very significant over this marine and coastal area. On 28 December 2020, the Gulf of Naples was hit by an extreme sea storm, with severe consequences. This study focuses on the waterfront area of Via Partenope, where the waves overrun the roadway, causing massive damage on coastal seawall, road edges, and touristic structures (primarily restaurants). Based on the analysis of the meteorological evolution of the sea storm and its effects on the waterfront, we suggest that reflective processes induced on the sea waves by the tuff cliffs at the base of Castel dell’Ovo had an impact in enhancing the local-scale waves magnitude. This caused in turn severe flooding of the roadway and produced widespread damage along the coast. The analysis of the event of 28 December 2020, also suggests the need of an effective mitigation policy in the management of coastal issues induced by extreme sea storm events. Wind-based analysis and prediction of the sea wave conditions are currently discussed in the literature; however, critical information on wave height is often missing or not sufficient for reliable forecasting. In order to improve our ability to forecast the effects of sea storm events on the coastline, it is necessary to analyze all the components of the coastal wave system, including wave diffraction and reflection phenomena and the tidal change. Our results suggest in fact that only an integrated approach to the analysis of all the physical and anthropic components of coastal system may provide a correct base of information for the stakeholders to address coastal zone planning and protection.

Short-duration rainfall extremes in Mediterranean regions are frequently produced by convective storms that concentrate most precipitation within narrow temporal windows. Standard Depth–Duration–Frequency (DDF) and Intensity–Duration–Frequency (IDF) approaches convert a selected duration and return period into constant-intensity design storms, neglecting the temporal structure that governs runoff generation in fast-responding catchments. This study quantifies the bias introduced by this simplification using long-term 10 min rainfall records and a duration-consistent event-selection procedure. Events lasting 30, 40, 50 and 60 min were extracted from local VAPI(Progetto Speciale per la Valutazione delle Piene in Italia) DDF relationships and converted into dimensionless temporal profiles; hydrological sensitivity, however, was evaluated only for the 30- and 40 min storms, as longer durations were included solely in the rainfall analysis. The 30- and 40 min profiles exhibit marked convective concentration, with the most intense 10 min interval contributing up to 41.8% and 31.7% of total rainfall. Controlled SWMM (Storm Water Management Model) 5.2 simulations on a conceptual 6-ha peri-urban catchment, performed within a non-predictive sensitivity experiment, show that variable-intensity storms tend to increase peak discharge and shorten time to peak compared with constant-intensity storms of identical depth. These results indicate that constant-intensity DDF/IDF storms may underestimate peak runoff for short durations, underscoring the importance of incorporating locally derived temporal rainfall profiles in Mediterranean environments characterized by increasingly irregularshort-duration convective rainfall.