This article provides a general methodology for calculating the retreat of the coastline and the volume of sand necessary to renourish a beach due to sea level rise (SLR) in the medium-long term. An example is presented, Victoria Beach, and a projection is made for the years 2030, 2040, 2050, and 2100. The results obtained take into account global sea level rise (GSLR), which is worldwide, and local sea level rise (LSLR), which considers climate variability and vertical land movements. Regarding GSLR, data were provided by the projections from IPCC (Intergovernmental Panel on Climate Change) scenarios and empirical models, such as Rahmstorf and Pfeffer. The LSLR data came from the tide gauge station located in Cadiz. Finally, the results obtained showed that global warming impacts erosive effects and the subsequent volume of sand required to renourish beaches. The total sea level rise (TSLR) projections indicated for Victoria Beach are relatively higher than the GSLR projections. Even in the best IPCC scenario (RCP 2.6), Victoria Beach presents a significant erosion of 52 m, requiring a volume of sand of 1.0 Mm³ to supply renourishment.

From a risk management perspective, compound events are very relevant because they can significantly increase the intensity and/or the spatial and temporal extension of the impact. Thus, depending on their magnitude, they may overwhelm the capability of emergency-response services to cope with “unusual” situations of major damage and respond to a large number of emergency situations throughout the region at the same time, and/or have to maintain the level of response during a relatively long period of time. When an extreme compound event occurs, its characteristics depart from the idealized conditions that are usually analyzed and, from the risk management perspective, the problem becomes highly multidimensional. This will be illustrated with the impact of the Gloria storm on the Spanish Mediterranean coast in January 2020. During five days extreme conditions (with some record breakings) of multiple hazards (wind, waves, rainfall, river discharge and surge) were recorded. In places such as the mouth of the Tordera River, they occurred simultaneously, but the most common situation was that different extreme conditions of univariate hazard occurred in remote areas of the territory, although they had to be managed simultaneously. In addition, the storm caused massive damage of various kinds, affecting transportation infrastructure, railway services, breakwaters, docks, urban services, housing, agricultural land and four fatalities in Catalonia. As a result of this, although the storm lasted about five days, the management of its impacts was much more extended, so that several months later some repairs were still being carried out. Looking to the event, the analysis of its probability of occurrence will be significantly affected by the adopted perspective. Thus, from the “physical” point of view, the analysis would range from the simplest joint probability of some hazards occurring in a given location (classical 2-drivers multivariate events) to multiple hazards over the whole territory (spatially compound with up to four concurrent hazards). From a "management" point of view, the analysis would focus on the probability of different types of damage (and their corresponding services) occurring at the same time, and on the probability of providing services in remote parts of the territory (and, consequently, dividing the available services) within a short period of time. To illustrate this possible multidimensional study plane, we will map the compoundness of the Gloria storm encompassing its induced hazards, impacts, damage and response. This work was supported by the Spanish Agency of Research in the framework of the C3RiskMed project (PID2020-113638RB-C21/ AEI / 10.13039/501100011033).

Compound flooding arises when multiple hydrometeorological drivers co-occur and interact, amplifying risk beyond that expected from individual hazards. This work analyses Storm Gloria (19–25 January 2020, E Spain) as a paradigmatic compound event in the Mediterranean region. The coastal strip considered here extends for 1,609 km (from the French border to Málaga) and includes 8.4 million inhabitants in 12,167 km². The event affected 770 municipalities caused 13 fatalities and four missing persons and generated about EUR₂₀₂₂ 204 million in Spain's Insurance Compensation (CCS) payouts. The analysis combines daily precipitation (P₍₂₄ₕ₎; 662 AEMET rain gauges), maximum wind gusts (140 stations), and significant wave height (Hₛ; 50 SIMAR/CoExMed points) with municipality-level CCS compensation data. The event window is objectively defined (≥ 40 mm day⁻¹ at ≥ 2 stations), and hazard severity is mapped using operational thresholds (P₂₄ₕ = 40/100/200 mm; Hₛ = 2/5/7 m; wind gusts ≈ 70/90/100 km h⁻¹). Multivariate (river and sea flooding at the Tordera River mouth) and spatially compounding (flooding in the Júcar basin and sea storm in the Gulf of Jávea) cases are quantified through a two-sided conditional framework and copulas in two areas located in the northern and central part of the study region, respectively, whereas the temporally compounding case is evaluated empirically from heavy-rainfall episodes in the Segura basin, located in the southern part. Results indicate that, for the first case, the return period of the maximum recorded precipitation is estimated at 24 years; however, when the compound event – where wave action hindered the discharge of the Tordera River into the sea – is taken into account, the estimated return period increases to 85 years. In the second case, it goes from 1.5 years to 72 years, while in the third, the return period corresponding to the time sequence of three heavy rainfall events in the same basin, becomes 22 years. Overall, the largest compensation values tend to occur where hazard levels are highest, although exposure, vulnerability, and insurance coverage modulate the final impacts. This integrated workflow (objective event definition, threshold‑based hazard mapping, copula‑based joint recurrence, and impact linkage) provides a transferable, practice‑ready template for compound‑aware coastal risk assessment in Mediterranean settings and other coastal regions.

Compound flooding arises when multiple hydrometeorological drivers co-occur and interact, amplifying risk beyond that expected from individual hazards. This work analyses Storm Gloria (19–25 January 2020, E Spain) as a paradigmatic compound event in the Mediterranean region. The coastal strip considered here extends for 1,609 km (from the French border to Málaga) and includes 8.4 million inhabitants in 12,167 km². The event affected 770 municipalities caused 13 fatalities and four missing persons and generated about EUR₂₀₂₂ 204 million in Spain's Insurance Compensation (CCS) payouts. The analysis combines daily precipitation (P₍₂₄ₕ₎; 662 AEMET rain gauges), maximum wind gusts (140 stations), and significant wave height (Hₛ; 50 SIMAR/CoExMed points) with municipality-level CCS compensation data. The event window is objectively defined (≥ 40 mm day⁻¹ at ≥ 2 stations), and hazard severity is mapped using operational thresholds (P₂₄ₕ = 40/100/200 mm; Hₛ = 2/5/7 m; wind gusts ≈ 70/90/100 km h⁻¹). Multivariate (river and sea flooding at the Tordera River mouth) and spatially compounding (flooding in the Júcar basin and sea storm in the Gulf of Jávea) cases are quantified through a two-sided conditional framework and copulas in two areas located in the northern and central part of the study region, respectively, whereas the temporally compounding case is evaluated empirically from heavy-rainfall episodes in the Segura basin, located in the southern part. Results indicate that, for the first case, the return period of the maximum recorded precipitation is estimated at 24 years; however, when the compound event – where wave action hindered the discharge of the Tordera River into the sea – is taken into account, the estimated return period increases to 85 years. In the second case, it goes from 1.5 years to 72 years, while in the third, the return period corresponding to the time sequence of three heavy rainfall events in the same basin, becomes 22 years. Overall, the largest compensation values tend to occur where hazard levels are highest, although exposure, vulnerability, and insurance coverage modulate the final impacts. This integrated workflow (objective event definition, threshold‑based hazard mapping, copula‑based joint recurrence, and impact linkage) provides a transferable, practice‑ready template for compound‑aware coastal risk assessment in Mediterranean settings and other coastal regions.

Understanding the compounding threats of floods and sea storms in the Mediterranean is crucial in the context of climate change. For this reason, a holistic analysis of their interaction and its implications for coastal resilience is needed. According to Zscheischler et al (2020), compound events are defined as the combination of multiple drivers and/or hazards that contribute to societal or environmental risk and that can be responsible for many of the most severe weather and climate related impacts. To manage these situations more effectively, it is essential to identify and prioritize elements that can be controlled, such as infrastructure planning and early warning systems, while also improving the resilience of those elements that cannot be controlled, such as natural ecosystems. Through the integration of scientific research, stakeholder collaboration, and management and policy interventions, coastal communities can enhance their capacity to mitigate risks and adapt to the impacts of compound hydrometeorological events.In the framework of the C3Riskmed project, multidisciplinary research has been conducted to analyze compound events on the Spanish Peninsular Mediterranean coast. This communication introduces the compound events of floods, wind and sea storms recorded in the coastal municipalities covering a total 1,609 km of coastline between the Spanish-French border and Gibraltar. Their economic impact is analysed using Insurance Compensation Consortium (CCS) data and this is compared with the impact of non-compound events. A remarkability criterion, which integrates physical and socio-economic variables, and used to select the most important events, is introduced. Finally, a paradigmatic compound event such as the January 2020 storm "Gloria" is presented. Through detailed analysis of meteorological and impact data, key aspects of the dynamics and consequences of this compound event are shown. The lessons learned from Storm Gloria can be considered for the improvement of early warning systems, infrastructure planning, and community preparedness to mitigate the impacts of future extreme weather events.This research has been done in the framework of the C3Riskmed project, Grant PID2020-113638RB-C22 funded by MCIN/AEI/10.13039/501100011033.References:Zscheischler, J. et al., 2020, A typology of compound weather and climate events. Nature Reviews.