Laserfiche WebLink
atmospheric pressure. Storm surge is extremely dangerous, <br /> because it is capable of flooding large coastal areas. <br /> Inland Flooding — Occurs when moderate precipitation <br /> accumulates over several days, intense precipitation falls over <br /> a short period, or a river overflows because of an ice or debris <br /> jam, or dam or levee failure. <br /> Flash Flood—Caused by heavy or excessive rainfall in a short <br /> period of time, generally less than six hours. Flash floods are <br /> usually characterized by raging torrents after heavy rains that <br /> rip through river beds, urban streets, or mountain canyons <br /> sweeping everything before them. <br /> In Indian River County, several variations of flood hazards <br /> occur due to the different effects of severe thunderstorms, <br /> hurricanes, seasonal rains, and other weather-related <br /> conditions. For the majority of the County, the primary causes <br /> of flooding are hurricanes or tropical storms. However, the <br /> County's low-lying topography, combined with its subtropical <br /> climate, make it vulnerable to riverine as well as storm- <br /> associated flooding. <br /> Flooding in Indian River County results from one or a <br /> combination of both of the following meteorological events: <br /> • Tidal surge associated with northeasters, hurricanes, <br /> and tropical storms; and <br /> • Overflow from streams and swamps associated with <br /> rain runoff. <br /> When intense rainfall events occur, streams and drainage <br /> ditches tend to reach peak flood flow concurrently with tidal <br /> water conditions associated with coastal storm surge. This <br /> greatly increases the probability of flooding in the low-lying <br /> areas of the coastal zone. Areas along the Indian River are <br /> particularly susceptible to flooding under these conditions. The <br /> most flood prone areas in the eastern portion of the County <br /> feature poorly drained soils, a high water table, and relatively <br /> flat terrain, all of which contribute to their flooding problems. <br /> Flat terrain and heavily wooded areas aggravate flood <br /> problems by preventing rapid drainage in some areas. <br /> Indian River County Comprehensive Emergency Management Plan Basic Page 8 <br />