Built environment and agricultural value at risk from Hurricane Irma flooding in Florida (USA)

Flooding is the most costly type of natural disaster, as well as the most frequent. To provide risk-based flood insurance, providers must be able to accurately determine an asset’s risk of flooding. Additionally, after a flooding event, providers need to quickly determine the direct damages that occurred to verify insurance claims and assist affected communities. Many current approaches to flood risk and flood damage estimation use data or statistical extrapolation that add various sources of uncertainty into the final damage estimate. To reduce uncertainties in flood risk analyses, the objective of this research is to outline an approach to flood damage estimation conducted on a statewide scale while still estimating flood risk and damage on a structure-by-structure basis. This approach uses the observed flooding extent during and after Hurricane Irma in Florida, extracted from a collection of satellite images over the course of 8 days. The results show that residential structures had the largest exposure to flooding during Hurricane Irma, with estimates ranging from $300 million to $2 billion per county, for the three counties that were studied in depth. For agriculture, fruit crops were estimated to have a potential at-risk revenue of $38.2 million, and vegetables were estimated to have a value at risk of $940 million across all crops. With improvements in the data used, this approach can offer a quick and accurate assessment of flood damages directly after a flood hazard, which could reduce the recovery time and economic impacts to the affected communities.