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characteristics of a violent onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean. Since they are not actually related to tides, the term is considered misleading and its usage is discouraged by oceanographers. There is another phenomenon often confused with tsunamis called rogue waves. There remains debate as to whether these waves are related to tsunamis. They are included in this section as the mitigation plans address the threat in the same relative manner. The characteristics are: Unpredictable nature Little is known about the formation May be caused by regularly -spaced ocean swells that are magnified by currents or the atmosphere Historic Events. The history of big waves hitting Florida is short: • A powerful earthquake in Portugal in 1755 killed thousands there and launched a tsunami that hit much of the U.S. coast. Scientists don't know if that caused many deaths in Florida, which was sparsely populated at the time; An earthquake in Charleston, S.C., in 1886 triggered a wave that surged up the St. Johns River to Jacksonville, causing few if any deaths; An 18 -foot rogue wave flooded the parked cars of sunbathers on Daytona Beach without warning in 1992. This event, called a meteorological tsunami (or meteotsunami), was a tsunami -like wave phenomenon of meteorological origin. Tsunamis and meteotsunamis propagate in the water in the same way and have the same coastal dynamics. For an observer on the coast where it strikes, the two types would look the same and have the same impacts. Research is currently underway to better understand these events, with the goal of developing a protocol for issuing meteotsunami warnings along the U.S. coast. Scientists believe that is was a meteotsunami that hit Indian River County Comprehensive Emergency Management Plan Basic Page 62