Hurricane-induced Surge Research Articles

Combined Wind-Wave-Surge Hurricane-Induced Damage Prediction for Buildings

AbstractCoastal structures are subjected to multihazard events such as hurricanes which consist of hurricane-induced surge and waves as well as winds. Hurricanes are a common natural hazard in the ...

A coral-rubble ridge as evidence for hurricane overwash, Anegada (British Virgin Islands)

Abstract. A coral-rubble ridge fringes part of the north shore of Anegada, a low-lying island in the northern Caribbean. Both historical reports and the geological record underline its vulnerability to tsunami and hurricanes. In this study we document the sedimentary characteristics of a coral-rubble ridge, which extends discontinuously along 1.5–1.8 km of chiefly north-facing shores at Soldier Wash. The ridge is less distinctive and appears only in patches along the west-facing shoreline at Windless Bight, where the wave regime is calmer. It is located ca. 8 m from the fair-weather shore, has a maximum width of 15 m and a maximum thickness of 0.8 m. The lower seaward-facing slope of the ridge is relatively flat, probably due to successive reworking, whereas the upper seaward slope is steep and partly displays avalanching faces. The landward flank is gently sloping and terminates abruptly. The ridge is mainly composed of well-rounded, encrusted and bored coral rubble (average diameter of 16 cm) that has been reworked in the shallow marine environment prior to transport. Only a few pieces of angular beach rock and karstified Pleistocene limestone are incorporated. The components build a clast-supported framework. No sand is present in the interstices. Imbrication of flat clasts indicates a deposition during landward bed load transport. The ridge morphology, composition and related hydrodynamic conditions during its emplacement are typical for coral-rubble ridges deposited by hurricane-induced storm surges. In comparison, nearby evidence for tsunami inundation is very different because the tsunami-transported coral boulders on Anegada are much bigger (2 m) than the biggest components in the ridge, they are deposited much farther inland (up to 1.5 km), and the corals seem to have been freshly broken out of the reef by the tsunami. The age of the ridge is difficult to estimate. The dark grey surface of the ridge is caused by bioweathering by endolithic organisms that takes tens of years and may give a very rough estimate of the minimum age of the ridge. Storms and related surges that built the ridge were likely stronger than 2010 hurricane Earl, which attained category 4 north of the island. Earl was able to slightly rework the lower seaward part of the ridge, but transported only few and smaller pieces of coral rubble and sand onshore. Therefore, the coral-rubble ridge found at the north shore of Anegada may imply that the island is vulnerable to hurricane-induced surges of greater impact (in relation to storm path and intensity) compared with the any of the recently documented storms which were only able to rework the ridge.

Regional loss estimation due to hurricane wind and hurricane-induced surge considering climate variability

This paper presents a framework to assess the potential hurricane damage risks to residential construction. Studies show that hurricane wind, frequency and/or hurricane-induced surge may change as a result of climate change; therefore, hurricane risk assessments should be capable of accounting for the impacts climate change. The framework includes a hurricane wind field model, hurricane-induced surge height model and hurricane vulnerability models. Three case study locations (Miami-Dade County, FL; New Hanover County, NC and Galveston County, TX) are presented for two types of analyses: annual regional loss estimation and event-based regional loss estimation. Demographic information, such as median house value and changes in house numbers, and distribution of houses for different exposures, is used to estimate the time-dependent probability of damage with or without possible climate change-induced change in wind speed, frequency and/or surge height. Through both analyses, it was found that climate change may have a significant impact on regional hurricane damage losses.

Social vulnerability index for coastal communities at risk to hurricane hazard and a changing climate

This paper presents the development of the Coastal Community Social Vulnerability Index (CCSVI) in order to quantify the social vulnerability of hurricane-prone areas under various scenarios of climate change. The 2004–2005 Atlantic hurricane seasons is estimated to have caused $150 billion dollars in damages, and in recent years, the annual hurricane damage in the United States is estimated at around $6 billion. Hurricane intensity or/and frequency may change due to the increase in sea surface temperature as a result of climate change. Climate change is also predicted to cause a rise in sea levels, potentially resulting in higher storm surges. The CCSVI combines the intensity of hurricanes and hurricane-induced surge to create a comprehensive index that considers the effects of a changing climate. The main contributing factors of social vulnerability (such as race, age, gender, and socioeconomic status) in hurricane-prone areas are identified through a principal components analysis. The impact of social characteristics on the potential hurricane damage under various scenarios of climate change are evaluated using Miami-Dade County, Florida, as a case study location. This study finds that climate change may have a significant impact on the CCSVI.

Engineering-Based Hurricane Risk Estimates and Comparison to Perceived Risks in Storm-Prone Areas

Shadow evacuees have negative effects on hurricane-induced evacuation operations. The goal of this study is to understand and explain shadow evacuation by comparing perceived risks with engineering risk estimates at the household level--particularly in nonevacuation zones where undesirable evacuation decisions are made--rather than by comparing perceived risks with regional hazards that previous studies have measured. A proposed methodology to compute engineering risk estimates from hurricane hazards is illustrated for approximately one million properties in Harris County, Texas. These risks are then compared with risk perceptions from a survey of residents which was conducted after Hurricane Ike's landfall in 2008. The results show that evacuation behavior is related to a hurricane-induced surge and wind risk mismatch and that risk overestimation and underestimation are more likely seen in locations near the waterways. The results also show that shadow evacuation is partly attributable to risk overestimation. The overestimation of damage risk from wind or surge correlates to 108,031 shadow evacuees. This is more than the total number of households in Galveston County that need to evacuate in the event of a hurricane--primarily through Harris County--and who may be subjected to traffic delays caused by shadow evacuees. The spatial distribution of risk mismatch provides opportunity for emergency managers to effectively plan and respond to hurricanes, while preventing unwanted evacuation.

Hurricane‐induced surge and currents on the Texas‐Louisiana shelf

This study consists of numerical model simulations of hurricane‐induced surge and currents on the Texas‐Louisiana shelf. The numerical experiment includes the simulation of multiple hurricane tracks with landfalling points along the Texas‐Louisiana coast. A parallel storm that traverses the entire Texas‐Louisiana coastline is also modeled to assess the difference in shelf response between landfalling and parallel storms. The grid extends from the Texas‐Mexico border to the Gulf Coast of Florida, with the ocean open boundary seaward of the shelf break. Along‐shelf and cross‐shelf surge and current variability are assessed as a function of shoreline geometry and bottom topography. A complementary one‐dimensional mixed layer model is used to evaluate the vertical structure of the currents and the maximum depth of hurricane influence. The choice of landfalling storm tracks is based principally on historical storm tracks for the Texas‐Louisiana area. Storm intensity, i.e., central pressure depression, for all storms is set equal to the 10‐year recurrence interval central pressure. Strong cyclonic flow is induced by the hurricane wind field within a distance from the storm's center equal to 3 to 5 times the storm's radius of maximum winds. Far‐field hurricane winds generate a northward moving coastal jet along the west coast of Florida, particularly for the landfalling storms. The far‐field continental shelf currents are topographically steered by the shoreline and bathymetry. There is strong evidence of a cyclonic‐anticyclonic eddy pair being generated in the wake of the parallel storm traveling eastward over the continental shelf. An intercomparison of the one‐ and two‐dimensional models shows that for depths less than 50 m, the combined use of the surge and mixed layer models permits a description of the vertical and horizontal hurricane‐induced current patterns. The surge height computations for a given storm strength point to the importance of several factors that determine surge levels as a function of offshore distance. These factors are bathymetry, topography, angle of approach of the storm, distance to landfall location, and shelf width. The most dramatic increase in surge levels occurs in depths less than 10 m, where the surge profile mirrors the changes in the bottom slope. In contrast, the sensitivity of surge dynamics to shelf width is neither strong nor consistent. A narrow spread of maximum surge values is observed. Each transect is examined individually to explain local behavior and the reason for the modest variation in surge values among dissimilar geographical areas. No critical dependence on the exact storm angle exists for storm angles within the range of angles associated with maximum surge generation (within 20° counterclockwise from the shore‐normal direction). Since the landfalling storms used in this study fall into this category, no significant dependence of surge height on the landfalling angle is observed.