storm surge storm surge coastal flood like phenomenon rising water commonly associated low pressure weather systems tropical cyclones strong extratropical cyclones severity affected orientation water body relative storm path timing tides casualties tropical cyclones occur result storm main meteorological factors contributing storm surge long winds inward storm low pressure induced dome water drawn trailing storm center historic storm deadliest storm surge record cyclone killed people area low lying coast particularly vulnerable caused tropical cyclones deadliest storm surge century caused killed people deadliest century caused killed people central philippines resulted economic losses estimated billion usd galveston hurricane category hurricane struck galveston texas drove devastating surge ashore lives lost making deadliest natural disaster strike united_states highest storm tide noted historical accounts produced cyclone estimated metres bay australia research published saw majority likely wave run steep coastal topography united_states greatest recorded storm generated hurricane katrina produced maximum storm surge metres communities mississippi record storm surge occurred area hurricane august highest storm tide record noted high water mark found got high storm surge occurred new_york_city hurricane sandy october high tide mechanics processes involved altering tide levels storms pressure effect direct wind effect effect earth rotation effect waves rainfall effect pressure effects tropical cyclone cause water level open ocean rise regions low atmospheric pressure fall regions high atmospheric pressure rising water level counteract low atmospheric pressure total pressure plane beneath water surface remains constant effect estimated increase sea level hpa drop atmospheric pressure strong surface winds cause surface currents degree angle wind direction effect known wind stresses cause phenomenon referred wind set tendency water levels increase shore decrease shore caused storm simply blowing water basin direction winds effects spread vertically water effect proportional depth pressure effect wind set open coast driven bays way astronomical tide earth rotation causes effect bends currents right left bend brings currents perpendicular contact shore surge bends current away shore effect surge effect waves directly powered wind distinct storm wind powered currents powerful wind large strong waves direction movement surface waves responsible little water transport open water responsible significant transport near shore waves breaking line parallel beach carry considerable water break water particles moving shore considerable momentum run sloping beach elevation mean water line exceed twice wave height breaking rainfall effect experienced predominantly hurricanes dump rainfall hours large areas higher rainfall localized areas result quickly surge water rivers drain increase water level near head tidal storm driven waters ocean meet rainfall flowing estuary surge wave heights shore affected configuration ocean narrow shelf steep drop shoreline subsequently produces deep water proximity shoreline tends produce lower surge higher powerful wave situation exemplified southeast coast florida edge water depths reach metres lies offshore florida offshore depth increases depth followed southward lies east upper keys conversely coastlines north_america gulf_of_mexico coast texas florida asia long gently sloping shelves shallow water depths gulf florida edge plateau lies kilometres offshore lying mainland shallow depths typically vary areas subject higher storm smaller waves difference deeper water surge dispersed away hurricane entering shallow gently sloping shelf surge dispersed driven ashore wind stresses hurricane topography land surface important element storm surge extent areas land lies meters sea level particular risk storm surge given topography surge height solely affected peak wind speed size storm affects peak surge storm water exit path sides escape mechanism reduced proportion surge force peak wind speed storm covers area asian region philippines affected storm lies path heading japan taiwan china vietnam extratropical storms similar tropical cyclones extra tropical storms cause offshore rise water unlike tropical cyclone storm surge extra tropical storms cause higher water levels large area longer periods time depending system factors storm size different steering winds system storm surge prone area longer periods time component extra tropical storm surge phenomenon negative water levels strong winds blowing offshore situations arise mean water levels bay fall significantly poses threat ships tied piers negative water levels severe ships tied docks actually sit preventing leaving port north_america extra tropical storm occur pacific alaska coasts north extra tropical storm possible gulf coast extra tropical cyclones affect coast march storm century november marked significant extratropical storm surge event east coast remnants hurricane developed easter southeast coast event storm force winds east present northern periphery low pressure center number days forcing water locations chesapeake_bay water levels rose significantly remained high feet normal numerous locations number days water continually built inside estuary onshore winds freshwater rains flowing bay locations water levels shy records feet measuring surge surge measured directly coastal tidal stations difference forecast tide observed rise water method measuring surge deployment pressure coastline ahead approaching tropical cyclone tested hurricane types sensors placed locations submerged accurately measure height water surge cyclone teams map high water marks land rigorous detailed process includes photos written descriptions marks denote location elevation flood waters storm event analyzed components water height broken portion surge identified mark classified storm surge classified storm tide land referenced vertical reference coordinate system evaluation divided categories based confidence mark evaluated excellent nhc post storm analysis surge different measures storm tide storm surge measurements storm tide measured vertical storm surge defined rise water expected normal movement tides storm surge measured tidal predictions assumption tide prediction known slowly varying region subject surge tides localized phenomenon storm surge measured relationship nearby tidal station tidal bench mark information station provides translation vertical mean sea level location tidal prediction yields surge height normal water height national_hurricane_center forecasts storm surge model stands sea lake hurricanes model accurate percent include central pressure tropical cyclone storm size cyclone forward motion track maximum sustained winds local topography bay river orientation depth sea astronomical tides physical features taken account grid referred basin overlapping basins defined southern eastern coastline continental storm use basin instance model runs basin basin northern gulf_of_mexico landfall final output model run display maximum envelope water occurred location allow track forecast usually model runs varying input parameters generated create map maximum hurricane evacuation studies family storms representative tracks region varying intensity eye diameter speed modeled produce worst case water heights tropical cyclone occurrence results studies typically generated thousand runs studies completed contract states available hurricane evacuation studies website include coastal county maps shaded identify minimum category hurricane result flooding area county meteorological surveys alert hurricanes severe storms areas risk coastal flooding particularly high specific storm surge warnings implemented instance netherlands spain united_states united_kingdom method introduced construction dams storm surge barriers open allow free passage close land threat storm surge major storm surge barriers netherlands delta works project protecting london russia modern development use netherlands creation housing communities edges wetlands floating structures restrained position vertical wetlands accommodate runoff causing damage structures protecting conventional structures somewhat higher low lying elevations provided prevent major surge intrusion mainland areas storm surge threat storm strikes land approaching
Storm surge