Use of ESWD and OPERA radar data for the rapid estimation of insured losses following hail storms.

Impact Forecasting (IF) is Aon’s Catastrophe Model development team. For several years, IF have been developing Automated Event Response (AER) services. These services aim to take either forecasts of upcoming events or observations immediately following events and use these to develop hazard footprints for input into operational catastrophe models. This allows for the rapid quantification of predicted losses from the event, either at market level or on individual clients’ exposures.

An AER service for windstorm in Europe has now been operational for several years and a service for hail is under development. Whilst there are not forecasts of hail that can be used for loss modelling, we are able to use observations following events.

In this work we demonstrate the use of two data sources for modelling hail losses. Firstly, the use of ESWD hail reports, and secondly the use of OPERA radar data alongside the ESWD reports. 2D radar reflectivity is combined with geopotential heights to derive the severe hail index and therefore the maximum estimated size of hail. The addition of the radar data allows for more accurate estimation of the area affected by hail and of the variation of hail size within the storm.

A brief overview of the operational IF European Hail model is also provided.