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4 . 1 . 5 Lightning <br /> 4. 1 . 5. 1 Hazard Identification <br /> Perhaps the most dangerous and costly effect of thunderstorms is ightning . As a <br /> thunderstorm grows , electrical charges build up within the cloud . Oppositely c harged <br /> particles gather at the ground below . The attraction between positive and nec ative charges <br /> quickly grows strong enough to overcome the air' s resistance to electrical flow . Racing <br /> toward each other , the charges connect and complete the electrical circuit . C iarge then <br /> surges upward from the ground at nearly one-third the speed of light and produces a bright <br /> flash of lightning ( Cappella , 1997 ) . <br /> Historic Events . On average , lightning kills more people than any other weather <br /> event . Florida leads in the nation in lightning related deaths and injuries . Most lightning strike <br /> fatalities occur in June , July , and August. Between 1959 and 1994 , there have been <br /> 345 lightning - related deaths in Florida ( National Lightning Safety Institute , 2004a ) . Florida <br /> also has the most strikes , about 12 strikes per square kilometer per year ins me places <br /> ( National Lightning Safety Institute , 2004b ) . Nationwide , lightning - related economic losses <br /> amount to over $5 billion dollars per year , and the airline industry alone loses approximately <br /> $ 2 billion a year in operating costs and passenger delays from lightning ( National Lightning <br /> Safety Institute , 2004c) . <br /> Between 1959 and 1996 , Indian River County recorded two lightni g - related <br /> deaths and four injuries . According to the NCDC , four major lightning incidents caused <br /> $ 1 , 050 , 000 in property damage . The majority of the damage came on 1 June 1997 when a <br /> lightning -related fire destroyed a million dollar home in Vero Beach . In the past 5 years , only <br /> two lightning events have been recorded with the NCDC — one event took place in Wabasso <br /> ( unincorporated County) and one in the City of Sebastian . <br /> Because lightning is a hazard that is not bounded by geographic c r topographic <br /> characteristics , there are no definite means to determine whether or not the E xtent of this <br /> hazard differs from jurisdiction to jurisdiction within Indian River County . <br /> 4. 1 . 5. 2 Vulnerability Assessment <br /> Lightning events can have the following potential impacts within a community : <br /> Excessive wind ; <br /> Excessive water; <br /> Damaging hail ; <br /> Electric power outage ; <br /> Surface and air transportation disruption ; <br /> Telecommunications system outage ; <br /> Human health and safety ; <br /> Psychological hardship ; <br /> Economic disruption ; <br /> Fire ; and <br /> Stormwater drainage impairment. <br /> 4-34 <br />