Constructing Probable Wind and Water Damage Sequences from Timelines — The Technical Perspective

Hurricane Katrina (2005) brought unrivaled destruction to buildings along the Mississippi Coast, generating thousands of property insurance claims. Hurricane Katrina had been a Saffir-Simpson Category 5 storm only 18 hours prior to making landfall at the Category 3 level along the Louisiana/Mississippi state line. At landfall, it still contained enormous potential for storm surge — far greater than the Category 3 landfall designation (based only on sustained windspeed) might indicate. As a result, damage from storm surge tended to be far more severe than damage from wind action, though many buildings sustained some levels of damage from both storm surge and wind. Exclusion of flood damage from standard property insurance policies has resulted in partial or full denial of many Hurricane Katrina-related damage claims, as District Court rulings in Mississippi have considered flood damage to include damage from storm surge. An unparalleled series of legal challenges has followed — pitting homeowners against insurers and requiring resolution of such questions as: 1 Was the residence destroyed by wind or water? 2 How much wind damage, if any, was sustained prior to the eventual destruction of the residence by storm surge? Settlement of these legal challenges has necessitated the separation of probable wind damage and storm-surge damage. The separation of damages is particularly complicated when structures have been completely destroyed or when engineers have been asked to determine wind and water damages long after critical evidence has been removed from the site. However, additional significant data concerning region-wide wind-speed and storm-surge levels (and the timing thereof) may not be available until several months after the hurricane, once detailed analysis of available region-wide observations has concluded. These regional timeline data provide a valuable resource for engineers in the reconstruction of probable wind/surge damage sequences some time after the hurricane damage has been removed.