A catastrophe model for Windstorm in Italy: developing a stochastic windstorm event set adjusted with open-access reanalysis datasets

Windstorms are one of the most destructive natural disasters in Europe, causing considerable human and economic impacts, ranging from fatalities and injuries to damage to agriculture, infrastructures, and properties. The European Commission’s Joint Research Centre (JRC) estimates annual losses of 5 €-billion for the European Union and United Kingdom (Spinoni et al., 2020). While in these areas there is not high confidence on the projected changes in windstorm intensity and frequency due to climate change (Ranasinghe et al., 2021), damages resulting from windstorms will most likely increase in the future due to the appreciation of asset values (Spinoni et al., 2020).

Although Italy is one of the most affected European countries, with annual absolute losses estimated above 0.5 €-billion (Spinoni et al., 2020), windstorm is still considered to be a secondary peril. However, severe windstorm events in the last few years (e.g., Storm Vaia in October 2018) have raised an increasing interest of the Italian insurance industry in understanding and modelling this peril.

In this context, we aim at developing a catastrophe model that quantifies the financial impacts of windstorms on the insurance market in Italy. To this aim, here we perform the calibration of a stochastic windstorm event set for the hazard component of the model. Uncalibrated footprints are obtained from simulation outputs of global and regional numerical models. Then, historical event footprints are extracted from open-access reanalysis datasets (e.g., ERA5, CERRA) and used to correct the climatology of the stochastic set and to adjust the wind-speeds of its individual events. This analysis is expected to be preparatory for the development of a comprehensive catastrophe model that combines wind hazard with exposure and vulnerability to assess windstorm-related financial losses in Italy.

 

References:

Ranasinghe, R., et al., 2021: Climate Change Information for Regional Impact and for Risk Assessment. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., et al., (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1767–1926, doi: 10.1017/9781009157896.014.

Spinoni, J., et al., 2020: Global warming and windstorm impacts in the EU, EUR 29960 EN, Publications Office of the European Union, Luxembourg, 2020, ISBN 978-92-76-12955-4, doi:10.2760/039014. JRC118595.