Open-source Risk Model for Hail Damages to Buildings and Cars: From Climatological Evaluation to Impact-based Warnings

Hail is a severe meteorological hazard that can cause significant damage to both buildings and cars. Here, we present the first-ever open-source risk model for hail damages, provided within the CLIMADA framework. The availability of high-resolution radar-based hail intensity measures and detailed damage and exposure data from local insurance companies in Switzerland allows for a spatially explicit calibration of vulnerability functions for buildings and cars. The model is able to provide climatological evaluations of hail risk and real-time hail damage estimates based on any user-provided exposure data. Furthermore, combined with crowd-sourced hail reports, the detailed damage data allows for an evaluation and uncertainty quantification of different radar-based hail intensity measures. In a second step, the model will be expanded to use high-resolution convection-resolving simulations with the hail growth module HAILCAST as hazard variable. This enables the assessment of hail risk under climate change, as well as the prototyping of an impact-based warning system based on ensemble weather forecasts. The open-source nature of the model allows for easy access and modification by any interested party, including insurance companies, government agencies, and the general public, making it a valuable tool for assessing hail risk and implementing effective mitigation strategies.