Sequential impact chains - a tool to explore compound and cascading impacts of weather extremes in the Alpine regions in the framework of the X-RISK-CC project

The assessment of risks related to weather and climate extremes in a specific area requires the understanding of the complex cause-effect chains that include all relevant factors and processes contributing to risk. In recent years, the Alps experienced intense meteorological events that caused compound impacts and domino effects with long-lasting consequences on the socio-economic systems. These events highlighted the need for an improved understanding of impacts of extreme weather events and of risk management adaptation in order to meet the challenges of the future.

To this aim, a conceptual impact-chain framework for the identification of predisposing and triggering conditions, hazards and subsequent impacts occurring at multiple time scales represents a suitable tool for setting up proper impact models and identifying risk management gaps. In this context, the visualization of the temporal sequence of involved processes is crucial. Impact chains are well-known conceptual models used for climate risk assessment, especially in the context of adaptation planning. They represent and interlink all climate risk components and are built in a participatory manner with stakeholders and experts integrating local data and knowledge of the past. The standard structure of impact chains reports impacts that can be caused by one or more climate or climate change factors, in present or future conditions, while the temporal evolution of a specific process is not explicitly reported.

In the framework of the Interreg Alpine Space X-RISK-CC project, the impact chain structure has been extended to conceptualize consequences of past extreme events by visualizing the temporal sequence of weather drivers inducing multiple compound (i.e. occurring at the same time) and cascading (i.e. domino effects) hazards and impacts. Weather drivers and non-climatic predisposing elements are linked to natural hazards which, in turn, are connected to subsequent socio-economic impacts acting on different time scales. Exposed sectors and vulnerability related to risk management are also linked to impacts and help to recognize the main management gaps and entry points for improvements.

These sequential impact chains were applied to conceptualize all targeted events in the Alps and used as basis for local workshops with stakeholders and experts focusing on the lesson learnt of risk preparedness and management for the examined events. This contribution presents the novel sequential impact chain framework and discusses the results of its application in the project areas.

The research leading to these results has received funding from Interreg Alpine Space Program 2021-27 under the project number ASP0100101, “How to adapt to changing weather eXtremes and associated compound and cascading RISKs in the context of Climate Change” (X-RISK-CC).