Transboundary Storm Risk and Impact Assessment in Alpine Regions

Late fall and winter storms are becoming more and more evident in the Alpine region, causing large ecological and socio-economic damages, e.g., storm Vaia (also known as Adrian), which affected Italy, Austria, France and Switzerland in the fall of 2018.

Such severe storm events may be influenced in their frequency and intensity by Climate Change; however, currently available tools for risk assessment and prevention are insufficient, especially on transboundary scales. Therefore, there is an increasing demand to provide decision makers and stakeholders with improved, harmonized and standardized tools and guidelines to enable efficient risk assessments for transboundary areas.

In the framework of the UCPM project (Union Civil Protection Mechanism) TRANS-ALP (Transboundary Storm Risk and Impact Assessment in Alpine Regions) institutions* from Italy and Austria are therefore working together to improve the impact prediction of such storm events for the area Trentino-Alto Adige/South Tyrol, Veneto as well as East Tyrol and the respective bordering regions, and to develop an integrated methodology for a multi-hazard risk assessment.

Based on meteorological observations as well as simulations, corresponding hazard intensity scenarios are being developed for historical storms. Weather information on individual storm events will be compiled in a database and used for a physically consistent recording of weather patterns causing damage.

BFW’s main contribution to TRANS-Alp is the analysis of approaches and methods for observing and mapping storm damages. Existing documentation approaches and data sources will be evaluated in terms of spatial scale and classification systems (i.e., degree of standardization), and recommendations for a harmonized transboundary classification system will be proposed.

The analysis of damages will also focus on potential cascading effects: Changes in forest cover after storms may have direct effects on landslides and avalanches (by creating new process areas), but also indirect, time-delayed effects by reducing the vitality and resilience of the remaining forest cover by, e.g., bark beetle outbreaks as secondary effects. To explore the effects of cleared and uncleared windthrow areas on avalanche formation, the BFW is collecting remote sensing and in situ data primarily using drone photogrammetry and snowpack observations in a pilot area. Based on these studies, methods and recommendations will be defined to support hazard and risk management in the Alpine region.

*) Eurac Research (Italy, Lead Partner), EPC – European Project Consulting srl (Italy), ARPAV – Agenzia Regionale per la Prevenzione e Protezione Ambientale del Veneto (Italy), ZAMG – Zentralanstalt für Meteorologie und Geodynamik (Austria)