Extreme Hurricane Research Articles

Impacts of Hurricane Maria on Land and Convection Modification Over Puerto Rico

AbstractHurricane Maria drastically altered the landscape across the island of Puerto Rico. This article investigates modifications to surface‐atmospheric interactions due to Hurricane Maria induced land damage and the associated impacts on local convective dynamics. Herein, we employed LANDSAT‐8 image mosaics to quantify the hurricane induced land modification. Results of the analysis indicate that the island suffered significant forest damage—much of which registered as a 28.35% increase in barren land and a 10.85% increase in pasture. Smaller changes included a decrease in cultivated agricultural land cover by 0.76%, along with wetland and water increases of 0.62% and 0.25%, respectively. Pre and postMaria land classifications were then assimilated into the Regional Atmospheric Modeling System cloud resolving model for the simulation of the June 23 to July 2, 2018 period under two land conditions. Results of the numerical experiments indicate that surface to atmosphere interactions were significantly modified when the land cover was altered, and that the highest deviations between pre and postMaria convection occurred over elevated areas with extreme hurricane induced land changes, such as the Cordillera Central mountain range and the El Yunque rainforest.

Extreme storm surges and waves and vulnerability of coastal bridges in New York City metropolitan region: an assessment based on Hurricane Sandy

Hurricane Sandy struck the New York metropolitan area in October 2012, becoming the second-costliest cyclone in the nation since 1900, and it serves as a valuable basis for investigating future extreme hurricane events in the area. This paper presents a hindcast study of storm surges and waves along the coast of the Mid-Atlantic Bight region during Hurricane Sandy using the FVCOM-SWAVE system, and its simulation results match observed data at a number of stations along the coastline. Then, as potential future scenarios, surges and waves in this region are predicted in synthetic hurricanes based on Hurricane Sandy’s parameters in association with sea-level rise in 50 and 100 years as well as with eight paths perturbed from that of Sandy. The prediction indicates that such surges and waves exhibit complex behaviors, and they can be much stronger than those during Hurricane Sandy. Finally, an assessment of hydraulic vulnerability is made for all coastal bridges in the New Jersey and New York region. It shows that hydrodynamic load and scour depth at some bridges may be worse in certain scenarios than those during Superstorm Sandy, while the probability of structural failure is small for the majority of them.

IMPROVED WIND DRAG FORMULATION FOR NUMERICAL STORM WAVE AND SURGE MODELING

The study proposes an enhanced method of computing wind drag coefficient (Cd) for extreme hurricane wind conditions which can be applied to precisely estimate the hurricane induced storm wave and surge. Thirty different tropical cyclone/hurricane conditions were chosen and modeled using the enhanced Wave Boundary Layer Model (WBLM) to estimate Cd based on air-sea interaction concept and are then subjected to polynomial regression with wind speed as an independent and Cd as the dependent variable. An improved wind drag (IWD) method (cubic function) that matches the WBLM's pattern at all simulated wind speeds was established. To evaluate the performance of the IWD method, it was used to simulate storm wave and surge levels for Hurricanes Katrina, Rita and Michael, along with two other widely used wind drag methods ( Garratt, 1977 and Zijlema et al., 2012 ). Katrina, Rita and Michael were chosen for their extreme wind intensity, the surge that they induced along their landfall regions and also the field data availability. The simulations were carried out using a coupled model to compute the wave heights and water levels, which were further compared and validated with the field measurements. A detailed analysis of the modeled results conveys the fact that the proposed IWD method performs better than the other two methods in accurate estimation of significant storm wave heights and peak surge levels. Hence, the study recommends the IWD method for computing Cd at extreme wind conditions up to 90 m/s.

Extreme hurricane rainfall affecting the Caribbean mitigated by the paris agreement goals

Hurricanes are among the most impactful extreme weather events affecting small island states such as the Caribbean and require long-term planning for community and infrastructure resilience. By coupling an offline dynamical hurricane model to the output of a large ensemble of global climate model simulations from the Half a degree of Additional warming Prognosis and Projected Impacts (HAPPI) project, we assess how the impacts of hurricanes may change under the Paris Climate goals. Specifically, we concentrate on hurricane rainfall over particular regions, with both the mobility and intensity of a hurricane being key drivers of local level impacts. For example, Hurricane Dorian (2019) caused widespread devastation when it stalled over Bahamas as a category 5 storm. We show that since 1970 only one other hurricane stalled at this strength: Hurricane Mitch (1998). Due to a combination of increased stalling and precipitation yield under a warmer world, our analysis indicates a greater likelihood of extreme hurricane rainfall occurring in the Caribbean under both Paris Agreement scenarios of 1.5 ∘C and 2 ∘C Global Warming goals, compared to present climate projections. Focusing on specific hurricane events, we show that a rainfall event equal in magnitude to Hurricane Maria is around half as likely to occur under the 1.5 ∘C Paris Agreement goal compared to a 2 ∘C warmer climate. Our results highlight the need for more research into hurricanes in the Caribbean, an area which has traditionally received far less attention than mainland USA and requires more comprehensive infrastructure planning.

Compounding impact of severe weather events fuels marine heatwave in the coastal ocean

Exposure to extreme events is a major concern in coastal regions where growing human populations and stressed natural ecosystems are at significant risk to such phenomena. However, the complex sequence of processes that transform an event from notable to extreme can be challenging to identify and hence, limit forecast abilities. Here, we show an extreme heat content event (i.e., a marine heatwave) in coastal waters of the northern Gulf of Mexico resulted from compounding effects of a tropical storm followed by an atmospheric heatwave. This newly identified process of generating extreme ocean temperatures occurred prior to landfall of Hurricane Michael during October of 2018 and, as critical contributor to storm intensity, likely contributed to the subsequent extreme hurricane. This pattern of compounding processes will also exacerbate other environmental problems in temperature-sensitive ecosystems (e.g., coral bleaching, hypoxia) and is expected to have expanding impacts under global warming predictions.

A Two-Stage Resilience Enhancement for Distribution Systems Under Hurricane Attacks

Hurricane events can cause severe consequences to the secure supply of electricity systems. This article designs a novel two-stage approach to minimize hurricane impact on distribution networks by automatic system operation. A dynamic hurricane model is developed, which has a variational wind intensity and moving path. The article then presents a two-stage resilience enhancement scheme that considers predisaster strengthening and postcatastrophe system reconfiguration. The pre-disaster stage evaluates load importance by an improved PageRank algorithm to help deploy the strengthening scheme precisely. Then, a combined soft open point and networked microgrid strategy is applied to enhance system resilience. Load curtailment is quantified considering both power unbalancing and the impact of line overloading. To promote computational efficiency, particle swarm optimization is applied to solve the designed model. A 33-bus electricity system is employed to demonstrate the effectiveness of the proposed method. The results clearly illustrate that the impact of hurricanes on load curtailment, which can be significantly reduced by appropriate network reconfiguration strategies. This model provides system operators a powerful tool to enhance the resilience of distribution systems against extreme hurricane events, reducing load curtailment.

North Atlantic Hurricane Winds in Warmer than Normal Seas

Tropical cyclones devastate coastlines around the world. The United States and surrounding areas experienced catastrophic extreme events in recent hurricane seasons. Understanding extreme hurricanes and how they change in a warming ocean environment is of the utmost importance. This study makes use of the historical, positive relationship between average summer sea surface temperatures (SSTs) and maximum hurricane wind speeds across the North Atlantic Basin from 1854–2018. Geographically weighted regression shows how the relationship between hurricane winds and SSTs varies across space. Each localized slope is used to increase historical wind speeds to represent winds in a three-degree Celsius warmer-than-average sea surface. The winds are then used to estimate the maximum intensity of the thirty-year hurricane (one with a 3.3% annual probability of occurrence) across the hexagonal grid using extreme value statistics. Viewing the results spatially allows for geographic patterns to emerge in the overall risk of major hurricane occurrence in warm SST environments. This study showcases the difference in the historical extreme compared to the potential future extreme in the hopes to better inform those charged with making important, life-saving decisions along the U.S. and neighboring coasts.

Extreme Atlantic Hurricane Probability of Occurrence Through the Metastatistical Extreme Value Distribution

AbstractThe estimation of extreme hurricane probability is hampered by small samples and by limitations in our models of extreme tropical storms. Current best estimates of extreme hurricane probability based on the traditional extreme value theory assume hurricane arrivals to be a homogeneous Poisson process. We reformulate here, for application to Atlantic hurricanes, the Metastatistical Extreme Value Distribution (MEVD) that relaxes this key assumption in the traditional extreme value theory and uses all available observations. The MEVD application to the 1886–2017 observational record improves the accuracy of extreme Atlantic hurricane estimation by about 50% with respect to current best estimates. The MEVD allows trends to emerge above estimation uncertainty: A sliding‐window analysis shows a significant increase in extreme hurricane likelihood in the past century. This trend, previously uncertain and controversial, remains significant after correcting for hurricane underdetection in the presatellite era and when focusing only on the modern observational period (1970–2017).

Vulnerability of coastal bridges under extreme hurricane conditions

Vulnerability of coastal bridges under extreme hurricane conditions

In the wake of a major hurricane: Differential effects on early vs. late successional seagrass species

AbstractAt least 18 major storms have struck the Gulf of Mexico and Caribbean in the past 50 yr including Hurricane Harvey, a Category 4 storm that passed over extensive seagrass beds in the western Gulf of Mexico and became the second‐most expensive U.S. hurricane. We sought to identify the effects of an extreme hurricane on sediment physicochemical characteristics and seagrass species with contrasting life histories and morphologies. Surprisingly, Harvey's intense wind speeds resulted in decreases in blade length, vegetative cover, and greater overall loss of Thalassia, a persistent climax species relative to Halodule, a prolific pioneer species. Sediment ammonium and grain size changed, but not organic carbon. Our results indicate that effects of wind intensity are not only restricted to the differential impacts on seagrasses, but on the physicochemical characteristics of the sediments. These changes, coupled with the slow colonization abilities of Thalassia, may prolong recovery of disturbed seagrass meadows.

Assessing the Multiple Impacts of Extreme Hurricanes in Southern New England, USA

The southern New England coast of the United States is particularly vulnerable to land-falling hurricanes because of its east-west orientation. The impact of two major hurricanes on the city of Providence (Rhode Island, USA) during the middle decades of the 20th century spurred the construction of the Fox Point Hurricane Barrier (FPHB) to protect the city from storm surge flooding. Although the Rhode Island/Narragansett Bay area has not experienced a major hurricane for several decades, increased coastal development along with potentially increased hurricane activity associated with climate change motivates an assessment of the impacts of a major hurricane on the region. The ocean/estuary response to an extreme hurricane is simulated using a high-resolution implementation of the ADvanced CIRCulation (ADCIRC) model coupled to the Precipitation-Runoff Modeling System (PRMS). The storm surge response in ADCIRC is first verified with a simulation of a historical hurricane that made landfall in southern New England. The storm surge and the hydrological models are then forced with winds and rainfall from a hypothetical hurricane dubbed “Rhody”, which has many of the characteristics of historical storms that have impacted the region. Rhody makes landfall just west of Narragansett Bay, and after passing north of the Bay, executes a loop to the east and the south before making a second landfall. Results are presented for three versions of Rhody, varying in the maximum wind speed at landfall. The storm surge resulting from the strongest Rhody version (weak Saffir–Simpson category five) during the first landfall exceeds 7 m in height in Providence at the north end of the Bay. This exceeds the height of the FPHB, resulting in flooding in Providence. A simulation including river inflow computed from the runoff model indicates that if the Barrier remains closed and its pumps fail (for example, because of a power outage or equipment failure), severe flooding occurs north of the FPHB due to impoundment of the river inflow. These results show that northern Narragansett Bay could be particularly vulnerable to both storm surge and rainfall-driven flooding, especially if the FPHB suffers a power outage. They also demonstrate that, for wind-driven storm surge alone under present sea level conditions, the FPHB will protect Providence for hurricanes less intense than category five.

Mangrove Disturbance and Response Following the 2017 Hurricane Season in Puerto Rico

Mangrove ecosystem responses to tropical cyclones have been well-documented over the last half century. Variability in tree mortality, aboveground biomass accumulation, canopy closure, and subsequent recovery has been explained by species, size, and geomorphology. This study gauges the initial response and short-term recovery of Puerto Rico’s mangroves following the 2017 hurricane season. Survival probability of tagged trees decreased with time, and the mean mortality across all sites was 22% after eleven months. Mean canopy closure loss was 51% one month after the hurricanes, and closure recovery rates decreased with time following the storms. Aboveground biomass accumulation decreased by 3.5 kg yr−1 per tree, corresponding to a reduction of 8.6 Mg ha−1 yr−1 at the stand level. Eleven months later, the mangroves recovered to 72% canopy closure and to nearly 60% of their pre-storm growth rates. Species, size, and geomorphology were found to play a role, while an influence of surrounding land cover and urbanization could not be detected. Larger trees suffered 25% more mortality than smaller size classes, and Laguncularia racemosa suffered 11% less mortality than other species. Forests in tidally restricted canals experienced more canopy loss but faster recovery than open embayment systems. Canopy closure for some forests is not forecasted to return to pre-storm levels in the next 20 years, which when combined with changes in hurricane frequencies may or may not be sooner than the next extreme hurricane disturbance. These findings suggest that size, species, and geomorphology are important in mangrove resilience to tropical storms and that urbanization does not play a role. Managing mangrove ecosystems for optimal shoreline protection will depend upon knowing which forests are at greatest risk in a future of changing tropical cyclone strength and frequency.

Integrating energy transferability into the connection-detail of coastal bridges using reinforced interfacial epoxy-polyurea reaction matrix composite

A new Carbon-fiber Interfacial Epoxy-Polyurea Matrix (C-IEPM) composite is investigated as a potential retrofit option for vulnerable girder-to-cap connection-details in coastal highway bridges. IEPM is a reaction of cross-linking epoxy with functional groups of pre-polymerized polyurea, producing an energy-transfer mechanism inherently absent in conventional carbon-fiber reinforced epoxy (CF/E) that drastically reduces the serviceability limit state during extreme hurricane events. IEPM is a covalently bonded interface, produced as a reaction of migrating epoxy species (epoxide and amine-based hardener), controlled as a function of their curing time (tc), with highly reactive isocyanate and amine polyurea moieties. To demonstrate IEPM effectiveness, six scaled concrete girders were tested using a modified simulated storm surge and slamming wave force function, derived using regional maps for a 100-year return-period Hurricane Katrina. Two girders, designed using current AASHTO field connection-details, failed catastrophically (concrete shear failure) in less than one-half load cycle. The CF/E-strengthened girder, failing in less than one load cycle, experienced severe damage to its girder-to-cap connection, including fiber and epoxy matrix breakage, delamination, unsustainable girder-end rotations, and transient force-displacement hystereses loops. However, after 12 load cycles, the C-IEPM-strengthened girder, providing substantial energy transferability (material damping) through its connection-details, experienced only local cracking.

Evaluating the Hydrodynamic Response of Coastal Bridges during an Extreme Weather Event

The frequency and intensity of recent hurricanes have demonstrated the need of taking proactive actions to prevent major damages during an extreme weather event. This work presents the results of a numerical study evaluating the hydrodynamic response of coastal bridges during an extreme hurricane event. A finite element model of a concrete bridge girder superstructure with a pier-substructure was developed in the commercial software Abaqus. The Coupled Eulerian-Lagrangian technique was used to model the interaction between water waves and the bridge as the structure deformed due to wave impacts. The wave velocity and the angle of wave impact were varied in the simulation to determine their effects on the response of the bridge. It was found that the resultant shear and uplift forces increase with wave velocity, while the angle of impact only had a significant effect on the resultant shear forces. The developed numerical framework will support further studies that will investigate variations in the bridge design and construction practices in order to enhance the resilience of coastal bridges against extreme weather events.

A Numerical Study on the Extreme Intensification of Hurricane Patricia (2015)

Abstract In October 2015 Hurricane Patricia stormed through the eastern Pacific, taking its place as the strongest hurricane in recorded history when its intensity reached a record breaking 185 kt (1 kt = 0.51 m s−1). Operational models and the National Hurricane Center’s official forecast failed to predict Patricia’s unprecedented intensification, provoking questions as to whether such an extreme event can actually be forecast. This study reports on the successful simulation of Patricia using a state-of-the-art high-resolution numerical weather prediction model. It was found that high model resolution (Δx ≤ 1 km), vortex initialization, and the parameterization of dissipative heating were key factors in realistically simulating Patricia’s intensity evolution. The simulation was used to investigate Patricia’s environment in terms of sea surface temperature, vertical wind shear, and humidity, under the premise that a simulation able to capture Patricia’s peak intensity would also accurately represent Patricia’s environment. Compared with a climatology derived from the Statistical Hurricane Intensity Prediction Scheme dataset, sea surface temperature ranked in the 99th percentile and environmental vertical wind shear in the 83rd percentile (ordered from high to low). However, humidity ranked more moderately. Ensemble forecasts indicate that Patricia had relatively high predictability in comparison to other well-studied rapid intensification cases such as 2010’s Hurricane Earl. The results from this study imply that high-resolution models are in principle able to predict the intensity of extreme hurricanes like Patricia.

ON THE INFLUENCE OF GLOBAL WARMING ON ATLANTIC HURRICANE FREQUENCY

Abstract. In this paper, the possible connection between the frequency of Atlantic hurricanes to the climate change, mainly the variation in the Atlantic Ocean surface temperature has been investigated. The correlation between the observed hurricane frequency for different categories of hurricane’s intensity and Sea Surface Temperature (SST) has been examined over the Atlantic Tropical Cyclogenesis Regions (ACR). The results suggest that in general, the frequency of hurricanes have a high correlation with SST. In particular, the frequency of extreme hurricanes with Category 5 intensity has the highest correlation coefficient (R = 0.82). In overall, the analyses in this work demonstrates the influence of the climate change condition on the Atlantic hurricanes and suggest a strong correlation between the frequency of extreme hurricanes and SST in the ACR.

Spatial and temporal variations in resilience to tropical cyclones along the United States coastline as determined by the multi-hazard hurricane impact level model

The United States coastline, where over 50% the population lives, is vulnerable to hurricanes along the East and Gulf coasts. However, the question remains as to whether these two areas are equally resilient to a landfalling hurricane. In addition, while it is assumed that improvements in building codes, infrastructure protections, and changing policy over the past century have been effective in reducing the impacts to a community from historically extreme hurricane events, such an assumption is still to be validated. Here, a multi-hazard artificial neural network model is used to address these questions. The Hurricane Impact Level Model is the first prediction model to utilize machine-learning techniques (artificial neural networks) to established complex connections between all meteorological factors (wind, pressure, storm surge, and precipitation resulting in inland flooding) of a tropical cyclone and how those interact with the location of landfall to produce a certain level of economic damage. This model allows for a more all-encompassing assessment of how the impacts of tropical cyclones vary along the coastline. The Hurricane Impact Level Model was trained with historical tropical cyclone events from 1998 to present day, resulting in established locational associations to modern relevant building codes and mitigation practices. Simulating the meteorological factors from historical events allows for a new assessment of economic impact changes due to infrastructure improvements and policy adaptations over time. In essence, if Hurricane Sandy hit Florida instead of New York, it would have a lower economic impact due to lower population density and more stringent building codes, which the artificial neural network has associated with the latitudes and longitudes within the state of Florida. If the Galveston hurricane were to hit today, the seawall would not succeed in lowering the economic impact to the Texas coastline. Over the years, significant effort has been put in to improving the resiliency of the United States coastline, mainly in the southern states, but it has not been enough to counteract the effects of population growth within coastal counties.

First Report of Copper-resistant Xanthomonas citri pv. citri Pathotype A Causing Asiatic Citrus Canker in Réunion, France

Xanthomonas citri pv. citri causes Asiatic citrus canker (ACC), which induces erumpent, callus-like lesions on all aerial organs, and consequently defoliation, premature fruit drop, and twig dieback under high inoculum pressure. Present in most tropical and subtropical citrus producing regions, the disease can lead to important decreases in yield and limitations to export markets due to the quarantine status of the pathogen in some countries ( Graham et al. 2004 ). Strains assigned to genetic lineage 1 within pathotype A, which has the widest host range comprising most citrus cultivars and citrus relatives, were shown to be primarily involved in the worldwide expansion of the bacterium over the 20th century ( Pruvost et al. 2014 ). ACC has been considered endemic in Reunion Island since the 1970s, but was likely present earlier and was not subjected to any eradication attempt. Most citrus growers on the island frequently apply copper-based pesticides as part of integrated pest management programs. A recurring lack of ACC control in several citrus groves was investigated in 2014 using our lab collection of authenticated X. citri pv. citri strains. A total of 501 strains from active epidemics as well as 123 historical strains isolated from 1978 onward were tested for copper resistance using PCR assays targeting copL ( Behlau et al. 2013 ). A total of 115 strains produced the expected amplicon whereas others (including all historical strains) and the negative control (H 2 O) did not. Phenotypic tests were carried out on low-complexing mineral salts casitone-yeast extract-glycerol-agar (CYE) plates ( Zevenhuizen et al. 1979 ) flooded with bacterial suspensions ( ≈ 5 × 10 6 cfu ml –1 ) in sterile tris buffer (pH 7.2), allowed to dry for 15 min., inoculated with a sterile CuSO 4 , 5H 2 O solution (10 mg ml –1 ) with an easySpiral plater used to create a gradient of log-increasing copper concentrations toward the plate center and incubated for 2 days at 28°C. Using this assay, copL + strains grew over a radius (measured from the plate periphery where the concentration of copper are lowest) >23 mm whereas copL – strains growth radius were constantly lower. Copper-resistant strains (CRS) had minimum inhibitory concentrations for copper sulfate ranging from 128 to 256 μ l ml –1 ( Pruvost et al. 1998 ). A subset of 20 CRS and 40 copper-susceptible strains (CSS) (including historical strains) were all assigned to genetic lineage 1 by minisatellite typing (performed as reported by Pruvost et al. 2014 ) and split into two multilocus haplotypes shared also with CSS. CRS were widespread in most citrus production areas of the island where they coexisted with CSS. The oldest CRS dated from 2010. Because no extreme hurricane hit the island between 2010 and 2014, the fast spread of CRS over the island was very likely related to their presence in a major citrus nursery, as confirmed by our data. In Reunion, the European Conformitas Agraria Communitatis (CAC) standards (directive 92/34/EEC) certify the disease-free status of citrus nursery plants (assessed by visual inspections for ACC). CAC is presently recommended but not compulsory. This report suggests that a strict implementation of this procedure would have helped limiting the spread of CRS in Reunion. (Resume d'auteur)

La Pintada landslide—A complex double-staged extreme event, Guerrero, Mexico

AbstractExtreme storms commonly trigger landslides in regions of humid, warm tropical climate causing loss of life and economic devastation. The tropical mountainous areas of Guerrero in southwest Mexico are frequently hit by extreme hurricanes and cyclones and thus prone to landslides. On 16 September 2013, a huge landslide resulted in 71 fatalities and destroyed a large part of La Pintada Village. We applied remote sensing techniques using the LIDAR DEM and high-resolution images of the La Pintada area, a post-landslide field survey, geotechnical laboratory tests of colluvium material from the landslide, and a slope stability analysis. We also interviewed eyewitnesses accounts of the event. Our results suggest that the 2013 La Pintada landslide was a complex and two-stage event. An intense four-day-long rainfall event related to the landfall of Hurricane Manuel resulted in the oversaturation of soil, which was the main factor that caused the landslide. The effect of rainfall was amplified by the lack of...

Hazard-Specific Supply Reactions in the Aftermath of Natural Disasters

Prior studies on the effects of catastrophes on insurance markets have either focused on one specific type of hazard or pooled several natural disasters. We argue that insurers evaluate disaster risk with respect to not only the frequency and severity of disasters but also the disaster type. We analyse U.S. property insurers’ supply decisions between 1992 and 2012 and find that insurers’ responses with respect to the reduction of business volume and exit decisions differ across hazards, even after controlling for damage size. The negative effects of catastrophes on supply decisions are more pronounced after extreme hurricane years compared with tornado years. We argue that supply distortions in the aftermath of unprecedented catastrophes are driven primarily by correlated losses besides the damage size of the event. Our results show that the predictability of catastrophe losses poses less-severe threats to insurers. Thus, we propose that insurers and regulators should focus primarily on measures that encourage diversification.