Abstract
Risk analysis within a multi-hazard context is particularly challenging due to the high level of uncertainty and the large number of driver factors creating a complex web of interconnected and cascading impacts. This complexity requires a comprehensive approach that allows us to unravel the intricate relationships among various risk factors and the timing of their occurrence. Analysing past disaster events is crucial for developing plausible risk scenarios, as it enhances our understanding of multi-hazard risk and forms the foundation for assessing current and future risks.
To tackle these complexities, the EC funded HORIZON project PARATUS examined past disaster events across four multi-hazard case studies: Romania, Turkey, the Caribbean, and the Alps. Each case study presented distinct geographic conditions, involved sectors, and risk profiles. Through forensic analysis and impact chain methodologies, the ongoing project has provided a comprehensive understanding of these disasters' complex interactions and consequences. This approach has enabled the development of an overall impact chain relevant to current risk assessments.
Although impact chains effectively frame and conceptualise risk elements through their connections and pathways, their visualisation is complex and often falls short, considering the temporal sequence between elements. To overcome this challenge, our study complemented the risk analysis with storylines. This method employs an episodic approach and is physically self-consistent in unfolding past events, articulating risk with an emphasis on plausibility rather than probability (Shepherd, 2018)1.
We explored storylines traversing different risk pathways within a complex impact chain, exploiting the findings from the forensic analysis to create well-defined narrative scenarios incorporating temporal sequencing. This improved understanding of the timing and occurrence of cascaded impacts and allowed for identifying sector-specific impact mechanisms or pathways, which would help to formulate targeted climate change adaptation or risk reduction measures.
This research used the Vaia storm as a case study, taking this integrative approach across the forestry, infrastructure, and tourism sectors in the Provinces of Bolzano and Trento, Italy. The findings indicate that the forestry sector suffered the most prolonged consequences, with economic and ecological losses that extended into other sectors. This was particularly evident in the reduction of the forest's protective functions, which increased vulnerability to subsequent hazards such as landslides and avalanches. The infrastructure sector faced immediate and substantial damage, requiring sustained recovery efforts beyond the initial response phase. Furthermore, the ecological and aesthetic degradation of the forest notably impacted the tourism sector, resulting in reduced visitor numbers over multiple seasons. These interconnected impacts highlight the importance of integrated, cross-sectoral strategies that account for cascading effects and temporal dimensions to strengthen regional resilience.
1 Shepherd, T. G. (2018). Storylines: An alternative approach to representing uncertainty in physical aspects of climate change. Climatic Change.