Hurricane Wind Research Articles

Storm surge and ponding explain mangrove dieback in southwest Florida following Hurricane Irma

Mangroves buffer inland ecosystems from hurricane winds and storm surge. However, their ability to withstand harsh cyclone conditions depends on plant resilience traits and geomorphology. Using airborne lidar and satellite imagery collected before and after Hurricane Irma, we estimated that 62% of mangroves in southwest Florida suffered canopy damage, with largest impacts in tall forests (>10 m). Mangroves on well-drained sites (83%) resprouted new leaves within one year after the storm. By contrast, in poorly-drained inland sites, we detected one of the largest mangrove diebacks on record (10,760 ha), triggered by Irma. We found evidence that the combination of low elevation (median = 9.4 cm asl), storm surge water levels (>1.4 m above the ground surface), and hydrologic isolation drove coastal forest vulnerability and were independent of tree height or wind exposure. Our results indicated that storm surge and ponding caused dieback, not wind. Tidal restoration and hydrologic management in these vulnerable, low-lying coastal areas can reduce mangrove mortality and improve resilience to future cyclones.

The lasting impacts of the Saffir-Simpson Hurricane Wind Scale on storm surge risk communication: The need for multidisciplinary research in addressing a multidisciplinary challenge

Historically, storm surge risk was indicated alongside the Saffir-Simpson Hurricane Wind Scale (SSHWS), and a lasting association remains among the general public. In recent years, the National Hurricane Center (NHC) has continually developed their advisories and products to explicitly communicate the storm surge hazard. In this study, we examine these developments to understand its impact on risk perception and discuss that though not explicitly, underlying associations to the SSHWS remain. We also find that despite the messaging produced through official storm surge guidance, the SSHWS continues to influence public perception and response. Our findings suggest that while improvements in storm surge messaging can improve risk communication and perception and ultimately save lives, it only addresses one component of the multidisciplinary system that defines storm surge risk. Truly effective resilience efforts will require comprehensive, multidisciplinary approaches.

Component-based fragility analysis of transmission towers subjected to hurricane wind load

The fragility model of transmission towers is one of the key elements for the hurricane risk and resilience assessment of regional power utility infrastructure. The current methods for fragility curve assessment of transmission towers rely on either static analysis or dynamic analysis with simplified demand parameters and limit state functions. The details of tower connections, such as joint eccentricities, rotational stiffness and slippage are often overlooked in fragility analyses due to the associated complexity of modeling and large computational effort. The purpose of this study is to model the realistic performance of transmission towers under hurricanes and develop a fragility curve estimation framework balancing between accuracy and efficiency.The correlated multivariate wind load time histories on the tower are simulated, and the load transferred from the cables to the cross-arms of the tower are generated using an effective analytical model. Two types of three dimensional finite element models of transmission towers are developed in the OpenSees platform. One is a complex model with all the joint details, which requires a very large computational effort to conduct nonlinear dynamic analyses, and the other one is a simple model without all the joint details, which is more computationally efficient. A small-scale dynamic probabilistic simulation with the two models is conducted, and a method to replace the complex model with the simple model is developed and validated. Using a high-performance computing cluster, medium-scale nonlinear dynamic time history analyses are carried out to obtain the demands of individual structural members and their correlation. Component-level failures are obtained via large-scale numerical simulations and are linked to global collapse of the tower through element removal and progressive collapse analyses. A case study of two transmission towers under hurricane is carried out. The results indicate that, compared to a traditional tip displacement method, the proposed component-based method with detail driven finite element model and large-scale simulations leads to a more accurate assessment of the transmission tower fragility curve.

Effects of Roll Vortices on the Evolution of Hurricane Harvey during Landfall

AbstractHorizontal boundary layer roll vortices are a series of large-scale turbulent eddies that prevail in a hurricane’s boundary layer. In this paper, a one-way nested sub-kilometer-scale large-eddy simulation (LES) based on the Weather Research and Forecasting (WRF) Model was used to examine the impact of roll vortices on the evolution of Hurricane Harvey around its landfall from 0000 UTC 25 August to 1800 UTC 27 August 2017. The simulation results imply that the turbulence in the LES can be attributed mainly to roll vortices. With the representation of roll vortices, the LES provided a better simulation of hurricane wind vertical structure and precipitation. In contrast, the mesoscale simulation with the YSU PBL scheme overestimated the precipitation for the hurricane over the ocean. Further analysis indicates that the roll vortices introduced a positive vertical flux and thinner inflow layer, whereas a negative flux maintained the maximum tangential wind at around 400 m above ground. During hurricane landfall, the weak negative flux maintained the higher wind in the LES. The overestimated low-level vertical flux in the mesoscale simulation with the YSU scheme led to overestimated hurricane intensity over the ocean and accelerated the decay of the hurricane during landfall. Rainfall analysis reveals that the roll vortices led to a weak updraft and insufficient water vapor supply in the LES. For the simulation with the YSU scheme, the strong updraft combined with surplus water vapor eventually led to unrealistic heavy rainfall for the hurricane over the ocean.

Upper Pleistocene and Holocene Storm Deposits Eroded from the Granodiorite Coast on Isla San Diego (Baja California Sur, Mexico)

This project examines the role of hurricane-strength events likely to have exceeded 119 km/h in wind speed that entered the Gulf of California from the open Pacific Ocean during Late Pleistocene and Holocene times to impact the granodiorite shoreline on Isla San Diego. Conglomerate dominated by large, ellipsoidal to subspherical boulders at the islands south end were canvassed at six stations. A total of 200 individual cobbles and boulders were systematically measured in three dimensions, providing the database for analyses of variations in clast shape and size. The project’s goal was to apply mathematical equations elaborated after Nott (2003) with subsequent refinements to estimate individual wave heights necessary to lift igneous blocks from the joint-bound and exfoliated coast on Isla San Diego. On average, wave heights on the order of 3 m are calculated as having impacted the Late Pleistocene rocky coastline on Isla San Diego during storms, although the largest boulders more than a meter in diameter are estimated to weigh two metric tons and would have required waves in excess of 10 m for extraction. Described for the first time, a fossil marine biota associated with the boulder beds confirms a littoral-to-very-shallow water setting correlated with Marine Isotope Substage 5e approximately 125,000 years ago. A narrow submarine ridge consisting, in part, of loose cobbles and boulders extends for 1.4 km to the southwest from the island’s tip, suggesting that Holocene storms continued to transport rock debris removed from the shore. The historical record of events registered on the Saffir–Simpson Hurricane Wind Scale in the Gulf of California suggests that major storms with the same intensity struck the island in earlier times.

Ocean–Atmosphere Interactions during Hurricanes Marco and Laura (2020)

During August of the 2020 Atlantic Hurricane Season, the Gulf of Mexico (GoM) was affected by two subsequent storms, Hurricanes Marco and Laura. Hurricane Marco entered the GoM first (22 August) and was briefly promoted to a Category 1 storm. Hurricane Laura followed Marco closely (25 August) and attained Category 4 status after a period of rapid intensification. Typically, hurricanes do not form this close together; this study aims to explain the existence of both hurricanes through the analysis of air-sea fluxes, local thermodynamics, and upper-level circulation. The GoM and its quality of warm, high ocean heat content waters proved to be a resilient and powerful reservoir of heat and moisture fuel for both hurricanes; however, an area of lower ocean heat content due to circulation dynamics was crucial in the evolution of both Marco and Laura. An analysis of wind shear further explained the evolution of both hurricanes. Furthermore, a suite of satellite observations and ocean model outputs were used to evaluate the biophysical modulations in the GoM. The cold core eddy (CCE) and Mississippi River surface plume had the greatest biophysical oceanic responses; the oceanic modulations were initialized by Marco and extended temporally and spatially by Laura. Reduced sea surface temperatures (SST), changes in sea surface salinity (SSS), and changes in Chlorophyll-a (Chl-a) concentrations are related to translation speeds, and respective contributions of hurricane winds and precipitation are evaluated in this work.

30-Year Changes in Oak-Hornbeam Forest after Windthrow

Hurricane winds are one of the most important abiotic factors in shaping the structure of the forest and the processes that occur in it. The aim of research was to determine regeneration processes and changes in the structure of forest stands caused by the windstorm in 1983. The research, based on stand tables from the years 1982, 1984, 1989 and 2014, was carried out on nine permanent research plots in the Białowieża Forest. The mean number of trees (MNT) taller than 1.30 m decreased by 13.7% after the windstorm. In 2014, MNT increased compared to 1984 (142%) and 1989 (53%). A significant decrease in the share of Picea abies (L.) H. Karst., thicker than 7 cm DBH and a significant increase in the share of Carpinus betulus L. was observed. Species richness for trees thicker than 7 cm DBH indicated a significantly lower species richness in 1982 and 1984 (12 species) compared to 1989 (14) and 2014 (16). The windstorm did not have a direct effect on the species richness, species composition of stands or the distinguished tree layers, except for trees thicker than 55 cm DBH. The observed changes in tree density in the lower layers of the stand prove that the regeneration process does not start immediately and continues even 30 years after the windstorm. Intermediate-severity windthrow accelerated natural changes in the stand structure.

Potential Hurricane Wind Risk to US Rural and Urban Forests

Abstract Hurricanes cause billions of dollars in damage annually in the United States and are projected to increase in intensity in the coming years. By exploring historical patterns of hurricanes and exposure of these hurricane-force winds across the landscape, areas of potentially high threat to future hurricane winds can be revealed. Combining potential threats from hurricane winds with forest data reveal the areas with the greatest potential threats to this important resource. Not surprisingly, most of the threats to forests occur in the Southeast, but the greatest threats to urban forests overall occur along the Northeast coast and in metropolitan centers in the Southeast. Overall, 4.6% of the nation’s rural forest basal area is within zones of the highest risk from hurricane winds. Information on regional and local scale variations in hurricane risk can be used to aid policies and local forest management to improve forest health and sustainability.

CFD-Based Evaluation of Elevated Coastal Residential Buildings under Hurricane Wind Loads

Abstract Many elevated houses in coastal areas have suffered serious wind-induced damage during hurricanes; this indicates the need for better understanding of the performance of elevated homes sub...

Scrambling and Reorientation of Classical Atmospheric Boundary Layer Turbulence in Hurricane Winds

AbstractThe societal, economic, and ecosystem consequences of hurricanes are projected to increase with ocean warming. Although wind gusts can be highly destructive in these extreme events, current knowledge on hurricane turbulence structures is limited due to insufficient measurement sampling data and the low resolution (1–5 km) of weather models. To bridge this knowledge gap, we propose and validate a numerical approach based on a novel theoretical framework that enables us to simulate hurricane boundary layer (BL) at ≈25 m resolution. Our high‐resolution simulations revealed an intermediate layer in the hurricane BL in which the streamwise‐elongated coherent turbulence structures that typically populate the BL flows are broken into smaller eddies. The distinctive structure of turbulence in cyclonic winds also alters internal BL dynamics during hurricane landfalls by reorienting the roll vortices. We demonstrate that the centrifugal forces in hurricanes cause scrambling and reorientation of the elongated conventional atmospheric BL streaks.

Predictive Model for Hurricane Wind Hazard under Changing Climate Conditions

AbstractHurricanes are among the most destructive and costly extreme weather events. The intensity of future hurricanes is generally expected to increase due to climate change effects. In this work...

Comparative Review and Assessment of Various Flood Retrofit Methods for Low-Rise Residential Buildings in Coastal Areas

Recent hurricanes indicated that retrofitted residential buildings are still susceptible to wind- and flood-induced damage in coastal areas. This poor performance indicates that flood retrofit methods need to be evaluated in terms of efficiency and effectiveness to resist hurricane wind and flood loads. This paper discusses various aspects in the hurricane-resistant design and retrofit of coastal residential buildings, including potential wind and flood-induced damage, risk mitigation, cost of retrofit methods, and the need for better standards. The cost analysis is performed for a typical one-story wood-frame residential building with a gable roof system considering several flood retrofit methods. The result indicates that selecting a flood protection level higher than the basic 100-year flood level can significantly decrease the risk of damage. This result seems appropriate and essential for specific hurricane-prone regions considering recent changes in the intensity/frequency of storms. A review of actual damage types indicates that wood-frame elevated houses are susceptible to experiencing wind-induced damage to the structural system and more extensive damage to the envelope system. The performance of breakaway walls below the base flood elevation (BFE) strongly depends on the connections between such walls and structural members. The result of cost analysis indicates that the foundation type can directly affect the total cost of retrofit solutions, such as elevation, wet, and dry methods for houses in coastal areas. Regarding the elevation method, adding a freeboard higher than the BFE does not significantly increase the total cost once the elevation method is selected as the preferred retrofit solution.

Recent Rebounding of the Post‐Landfall Hurricane Wind Decay Period Over the Continental United States

AbstractThe hurricane post‐landfall wind speed decay is closely linked to the inland damage potential. We introduce the wind decay period as a new metric for assessing the time required for a landfalling hurricane to dissipate to the intensity below tropical storm strength. In the continental United States, the wind decay period was generally decreasing during 1900–1979 but significantly increased during 1980–2019. The 120‐year trend pattern of the wind decay period has been found to be correlated with the Atlantic Multidecadal Oscillation. Meanwhile, we show that the storm's distance of movement is not changing simultaneously with the decay period due to the variance of storm translation speed. The spatial variation of the wind decay is also confirmed. While the majority of the historical Gulf landfall hurricanes decayed below tropical storm strength, landfalling hurricanes over Florida in particular, tend to cross the peninsula retaining wind speeds greater than 34‐kt.

Dysfunctionality Hazard Curve: Risk-Based Tool to Support the Resilient Design of Systems Subjected to Multihazards

While resilience metrics have been proposed and studied given a functionality recovery curve, they have not emphasized enough on accounting for the uncertainties in multihazard occurrences and intensities. Moreover, these resilience metrics are not risk-based (i.e., they do not express the system’s resilience loss as a frequency of exceedance), leading to inconsistencies in system performance description when compared to performance-based engineering frameworks. A risk-based tool termed the dysfunctionality hazard curve is proposed to assess the resilience of systems subjected to single hazards or multihazards with interevent dependencies. The dysfunctionality hazard curve expresses system resilience performance as frequency of exceedance of time to full functionality. In doing so, it characterizes system recovery as a sequence of repair activities and also considers the uncertainties in the multihazard occurrences and intensities. The dysfunctionality hazard curve is demonstrated for a residential building susceptible to earthquake and hurricane hazards. Results indicate that the dysfunctionality hazard curve for earthquakes is greater than that for hurricane winds under single hazards. Under multihazards, considering interevent dependencies during system recovery rather than ignoring them leads to a larger dysfunctionality hazard curve. Finally, the concept of the dysfunctionality hazard curve is also extended to a system-of-systems consisting of residential and commercial buildings.

On the Role of the Explosive Interaction of Three Surface Waves at the Initial Stage of Spray Generation in Strong Winds

This work is devoted to a theoretical study of the hydrodynamic instability of the water–air interface. The development of this instability may result in “bag-breakup” fragmentation, which is one of the main sources of droplets in hurricane winds. A hypothesis according to which the initial water surface elevations subjected to fragmentation are formed by the hydrodynamic instability of disturbances of the wind drift current in the water is proposed. The weakly nonlinear stage of instability in the form of a resonant three-wave interaction is considered. It is found that the nonlinear resonant interaction of a triad of wind drift perturbations, one wave of which is directed along the flow and two other waves are directed at an angle to the flow, leads to an explosive increase in amplitudes. As part of the piecewise continuous model of the drift current profile, the characteristic time and spatial scales of disturbances are found and it is shown that their characteristic dependences on the air friction velocity agree with previously obtained experimental data.

Achieving Residential Coastal Communities Resilient to Tropical Cyclones and Climate Change

Coastal cities in the Southeast and Gulf Coast of the United States are at an increased risk of tropical cyclones (hurricanes) due to the combined effects of urbanization, rapid economic development, and climate change. Current building codes and standards focus on minimum performance criteria for individual buildings exposed to severe hazard events to ensure occupant safety. However, they do not consider the resilience of buildings and building portfolios, which are key factors in determining whether a community can respond to and recover from a severe natural hazard event. Light-frame wood residential buildings dominate the residential market in the US, represent a significant percentage of the investment in the built environment, and are especially vulnerable to hurricane winds and storm surge in coastal areas. Our study of the impact of various hurricane and climate change scenarios on the performance of coastal residential communities reveals that decision-making at the community level is needed to develop rational engineering and urban planning policies, to mitigate the impact of hurricane wind and storm surge, and to adapt to climate change. The results suggest that fundamental changes in the current building regulatory process may be necessary.

Large eddy simulation of hurricane boundary layer turbulence and its application for power transmission system

Recent extreme hurricanes caused a huge loss in damages to critical civil infrastructure. To estimate hurricane wind loading on structures, spectral methods are widely used to generate neutral atmosphere boundary layer winds, which however are limited to describe extreme wind fields that are non-stationary and more turbulent. To overcome this limitation, a high-fidelity high-resolution computational model is developed to simulate hurricane wind field with detailed physics. A large eddy simulation (LES) solver is developed using a sub-grid-scale model based on open source program OpenFOAM. The simulated wind field is validated through comparison with observations. The generated wind field is applied to analyze structural response of a power transmission system. The proposed hurricane boundary layer (HBL) model and a neutral atmosphere boundary layer (ABL) model are compared in tropical storm and category-3 hurricane scenarios. Compared with the HBL model, the ABL model doesn’t consider the mesoscale terms and overestimates the crosswind velocity and the turbulent kinetic energy (TKE) near the ground. As a result, the ABL model overestimates the dynamic responses of the wires and towers. The developed HBL model captures the main characteristics of hurricane wind and is applicable for modeling civil infrastructure exposed to hurricanes at a large scale.

Poverty and hurricane risk exposure in Jamaica

This paper investigates the impact of hurricane risk exposure on poverty. To achieve this, we use a small area poverty mapping methodology to simulate our measure of poverty for households in Jamaica. Along with calculated hurricane wind exposure estimates that take account of the type of building material which matters for wind vulnerability, we calculate future risks for household poverty under different RCP8.5 climate change models. In general, we find that without wind resistant building material, substantial increases in poverty are likely under most models. The results are indicative of policy instruments needed to counteract the future risk of increases in poverty.

Evaluation of parametric wind models for more accurate modeling of storm surge: a case study of Hurricane Michael

Storm surge induced by hurricane is a major threat to the Gulf Coasts of the United States. A numerical modeling study was conducted to simulate the storm surge during Hurricane Michael, a category 5 hurricane that landed on the Florida Panhandle in 2018. A high-resolution model mesh was used in the ADCIRC hydrodynamic model to simulate storm surge and tides during the hurricane. Two parametric wind models, Holland 1980 model and Holland 2010 model, have been evaluated for their effects on the accuracy of storm surge modeling by comparing simulated and observed maximum water levels along the coast. The wind model parameters are determined by observed hurricane wind and pressure data. Results indicate that both Holland 1980 and Holland 2010 wind models produce reasonable accuracy in predicting maximum water level in Mexico Beach, with errors between 1 and 3.7%. Comparing to the observed peak water level of 4.74 m in Mexico Beach, Holland 1980 wind model with radius of 64-knot wind speed for parameter estimation results in the lowest error of 1%. For a given wind model, the wind profiles are also affected by the wind data used for parameter estimation. Away from hurricane eye wall, using radius of 64-knot wind speed for parameter estimation generally produces weaker wind than those using radius of 34-knot wind speed for parameter estimation. Comparing model simulated storm tides with 17 water marks observed along the coast, Holland 2010 wind model using radius of 34-knot wind speed for parameter estimation leads to the minimum mean absolute error. The results will provide a good reference for researchers to improve storm surge modeling. The validated model can be used to support coastal hazard mitigation planning.

The Great Havana Hurricane of 1846: A Reconstruction of the Storm’s Track, Intensity, and Impacts

This article reconstructed the track, intensity, and societal impacts of the Great Havana Hurricane of October 1846, using all available historical data, which include ship logs, newspapers, diaries, and early instrumental records. Most of the data were extracted from original manuscripts at historical libraries and repositories. Meteorological aspects of the hurricane were analyzed by mapping twice-daily surface synoptic weather maps from geographic information systems methods, estimating central pressures from known wind–pressure relationships derived from modern hurricane studies, and assessing intensity based on damage descriptions from the Saffir-Simpson Hurricane Wind Scale and an inland decay model. The storm was found to be much stronger than previously known. In this study, we clearly define the first known record of a landfalling Category 5 hurricane in the Atlantic Basin, which likely ranks among the top of all those known in the modern (1851–present) Atlantic Basin official hurricane database. Although this storm has been previously referred to as one of the most destructive hurricanes in the history of Cuba, the impacts of the Great Havana Hurricane actually spanned well beyond the Caribbean, tracking from Florida through many major populated cities along the East Coast and into Atlantic Canada. Clearly, such a storm today, with much larger metropolitan areas, would have caused enormous economic damage and should be anticipated in long-term hurricane mitigation, zoning, and worst-case scenarios. This study highlights the importance of examining historical documentary sources for extreme events, providing a framework on how to research case studies of premodern Atlantic hurricanes back in time.