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an aircraft's wing. The roof in effect becomes an airfoil that is <br />attempting to "take off" from the rest of the building. Roof <br />vortexes generally concentrate the wind's uplift force at the <br />corners of a roof. These key points can experience uplift <br />forces two to five times greater than those exerted on other <br />parts of the roof. <br />Once the envelope of the building has been breached through <br />the loss of a window or door, or because of roof damage, wind <br />pressure on internal surfaces becomes a factor. Openings <br />may cause pressurizing or depressurizing of a building. <br />Pressurizing pushes the walls out, while depressurizing will pull <br />the walls in. Internal pressure coupled with external suction <br />adds to the withdrawal force on sheathing fasteners. <br />Damages from internal pressure fluctuations may range from <br />blowouts of windows and doors to total building collapse due to <br />structural failure. <br />During Hurricane Andrew, catastrophic failure of one- and two- <br />story wood -frame buildings in residential areas was observed <br />more than catastrophic failures in other types of buildings. <br />Single-family residential construction is particularly vulnerable <br />because less engineering oversight is applied to its design and <br />construction. As opposed to hospitals and public buildings, <br />which are considered "fully engineered," and office and <br />industrial buildings, which are considered "marginally <br />engineered," residential construction is considered <br />"non -engineered." Historically, the bulk of wind damage <br />experienced nationwide has occurred to residential <br />construction. Fully engineered construction usually performs <br />well in high winds due to the attention given to connections and <br />load paths. <br />Hurricane winds generate massive quantities of debris that can <br />easily exceed a community's entire solid waste capacity by <br />three times or more. Debris removal is an integral first step <br />toward recovery, and as such, must be a critical concern of all <br />those tasked with emergency management and the restoration <br />of community services. <br />A storm surge is a large dome of water often 50 to 100 miles <br />wide and rising anywhere from 4 to 5 feet in a Category 1 <br />hurricane and up to 20 feet in a Category 5 storm. The storm <br />surge arrives ahead of the storm's actual landfall, and the <br />Indian River County Comprehensive Emergency Management Plan Basic Page 15 <br />