Vulnerability of buildings to windstorms and insurance loss estimation

Windstorms cause enormous loss to life and property worldwide. Insurance companies use risk assessment models to assess the financial risk to their insurance exposure due to windstorms. The estimation of the intensity of hazard and the vulnerability of buildings to windstorms are important parts of a windstorm risk assessment model. The vulnerability functions (or curves) are, in general, based on analyses of loss data from insurance companies. The loss data available from insurance companies following a natural disaster is generally comprised of losses representative of a wide variety of buildings, often lacking information on building-specific characteristics such as height and material. Analysis of such data may not go beyond the development of an aggregate (or generic) vulnerability curve for a combined portfolio giving no idea of the vulnerability of individual building types represented by this curve. The paper discusses the vulnerability of buildings to windstorms and the development of vulnerability functions for windstorm loss estimation. A methodology is presented for the disaggregation of a generic vulnerability curve into several curves representing individual building types. The methodology provides a convenient way of translating known vulnerabilities for a region to those for another region by combining them with actuarial data and building inventory information of the region. The methodology is applied for the disaggregation of generic vulnerability curves for the Caribbean Island of Puerto Rico. The hurricane hazards and the consequent property losses in the region are also discussed.