AIR Unveils Flood Model for Great Britain

AIR Worldwide Corp. (AIR) announced the availability of the AIR Inland Flood Model for Great Britain.

The new probabilistic model will help companies better manage on-and-off flood plain risk for properties in England, Wales, and Scotland. It covers residential and commercial lines of business including Alternative Living Expenses (ALE) and Business Interruption (BI). The model incorporates original research by AIR that has been peer-reviewed by a team of leading flood risk experts in the U.K.

The AIR Inland Flood Model for Great Britain captures storm systems of varying size—from large-scale events affecting the entire country to highly localized thunderstorms. Using results from Numerical Weather Prediction (NWP) modeling, AIR has developed an innovative and sophisticated rainfall generation module that produces a realistic simulation of rainfall patterns that account for storm duration and the geographic area of rainfall.

Additionally, AIR’s model incorporates a novel approach to estimating river run-off. The process incorporates pre-storm conditions based on five days of preceding rainfall activity, resulting in a long-term memory of pre-event soil conditions for each simulated event.

With approximately 50 percent of the losses from the 2007 floods occurring off-flood plain and much of that loss occurring in highly exposed urban areas, AIR developed an explicit model for off-flood plain loss estimation. The off-flood plain model accounts for elevation, runoff, and the impact of drainage backups, facility aging, and other urban risks at each modeled location.

AIR's model estimates damage to buildings and contents caused by flood, by incorporating damage functions that vary by occupancy, construction, and height. Since flood damage is highly dependent on height, AIR's model enables companies to analyze the risk to a specific floor or floors of interest, including basements. The model also accounts for alternative accommodation and the time required for drying and cleaning the property as well as business interruption losses which vary by occupancy and account for building size and complexity, and business characteristics such as resiliency and the ability to relocate.

Losses from the AIR Inland Flood Model for Great Britain have been validated through extensive analysis of personal and commercial lines claims data from the 2007 floods, representing roughly 30% of the industry exposure.