Deconstructing Wind Storm Impacts for Risk Assessment: The Role of Duration, Gust Factor, and Precipitation in Residential Building Damage in Germany

Severe storm events rank among the most damaging natural hazards in Central Europe, necessitating their detailed analysis within disaster risk management frameworks. Current storm risk assessments predominantly focus on maximum wind speed or wind gust as the sole hazard variable for estimating potential damage. However, wind storms are multifaceted phenomena, and a comprehensive understanding of their impact on residential buildings requires a broader evaluation of storm characteristics. This study aims to enhance risk assessments by incorporating multiple storm parameters, including storm duration, average storm intensity and precipitation during and after the event, to more accurately capture the vulnerability of residential buildings in Germany.Using a 28-year dataset of insured storm and hail damage at the county level - provided by the German Insurance Association - we implement generalized additive models to estimate vulnerability curves as functions of storm characteristics and precipitation. The hazard components are derived from ERA5 reanalysis data and include maximum wind speed, event duration, gust factor, and total precipitation associated with each storm event.Our results reaffirm that maximum wind speed is the dominant predictor of storm-related building damage in Germany. However, additional factors significantly influence loss ratios: longer storm durations correlate with increased damage, especially during less extreme events, and both higher precipitation totals and decreased gust factors are associated with greater losses. These findings emphasize the importance of a multi-variable approach to storm risk assessment and offer valuable insights for improving building resilience and insurance modeling.