Cascading effects of extreme storms and floods: Evidence on impact propagating mechanisms.

The increasing frequency and severity of extreme storms and floods in the Eastern Mediterranean under climate change pose significant challenges for modern societies. These events often trigger cascading effects that extend far beyond the immediate disaster zone, disrupting interconnected systems such as power, transportation, and communication networks. Despite advancements in flood risk management and growing awareness of cascading hazards, the mechanisms driving these interdependencies and their broader impacts remain poorly understood. This study investigates the cascading effects triggered by the catastrophic Storm Daniel, which struck Thessaly, Greece, in September 2023, as a case study to explore the nature, scale, and ways of impact propagation.

This work also provides an analysis of cascading effects, based on evidence on historical storm and flood disaster impacts in the Mediterranean region, identifying the interactions between primary hazards (flooding, landslides, erosion) and secondary consequences as well as the diverse sectors that suffer impacts. The analysis reveals different propagation mechanisms of these effects, highlighting the vulnerability of interconnected systems as well as the vulnerability of the natural and the built environment. The cascading effects identified underscore systemic risks of modern societies posed by extreme events, particularly in urban areas with dense, interdependent, and critical infrastructure.

The findings contribute to the growing body of literature on cascading disasters, addressing critical knowledge gaps in understanding how extreme weather events propagate through modern societal systems. These insights are particularly relevant in the context of climate change, which is expected to amplify the frequency and intensity of such events.