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Chapter•5:Hazard Analysis—Tropical Cyclones <br /> Description: <br /> Sum of the expected loss for each event (i.e., sum of the products of the estimated loss from <br /> each event and that event's rate of occurrence) <br /> A tool used to calculate AAL due to tropical cyclones is the HAZUS MH model. The wind <br /> speed recurrence intervals used by the HAZUS model are calculated based on the probability <br /> of tropical cyclone impacts, and high winds resulting from other effects (Kona Storms, high <br /> trade winds, etc.) are not specifically accounted for. Although the recurrence interval of these <br /> non-cyclonic wind storms is high, perhaps several storms per year, the magnitude of the <br /> winds and associated losses are generally small therefore it can be generally assumed that <br /> these storms will not contribute significantly to the AAL calculated for tropical cyclones. <br /> Based on a HAZUS AAL analysis incorporating Hawaii Construction Cost Data, tropical <br /> cyclone AAL is about $69 million in Hawaii County. The predominant contributor to loss is <br /> single-family residential construction. <br /> County Hawaii County <br /> Tropical Cyclone AAL $69 million per year <br /> The HAZUS model can also be used to determine probabilities of varying degrees of damage <br /> to site specific facilities. To determine AAL, HAZUS computes losses, Li, for seven <br /> earthquake scenario events with different return periods (1/exceedance probability): 10-year, <br /> 20-year, 50-year, 100-year, 200-year, 500-year, and 1000-year. The Probability versus Loss <br /> Curve is approximated through curve fitting, and the area under the fitted curve is integrated <br /> to obtain the AAL results. <br /> A risk assessment has been conducted for essential facilities in Hawaii County. From this <br /> analysis the facilities were ranked based on their expected losses and loss of functionality. <br /> 5.5 Mitigation Strategies <br /> 5.5.1 Previous/Current Efforts <br /> 5.5.1.1 Construction Standards <br /> As described in Chapter 4, the design vintage can be used as an indicator of a buildings <br /> susceptibility to wind damage. Design wind pressures, typical construction type (single or <br /> double wall), and use of hurricane uplift resistance can all be determined by the year built <br /> based on the corresponding version of the UBC or IBC in effect at the time. Table 5-5 and <br /> Table 5-6 provide statistics of the number of homes built under each version of the UBC and <br /> their probable uplift resistance. Most existing homes have no hurricane mitigation <br /> 5-13 Hawaii County Multi-Hazard Mitigation Plan <br />