Search

The projected increase in coastal risk requires a reevaluation of coastal risk reduction strategies. A multi-model approach is proposed to examine the variability of coastal storms influenced by climate change and El Niño Southern Oscillation (ENSO). To this end, the historic coastal storm of August 8 2015, resulting from a local extratropical cyclone (ETC) off the central Chilean coast, was analyzed through the coupling of the WRF atmospheric model, Delft3D FM (D-FLOW and D-WAVE modules), and EOT20 astronomical tide model. The results show that the characteristics of local ETCs are susceptible to regional temperature gradients associated with climate change and ENSO. The coastal storm of August 8 2015, presented a decrease in wave height and counterclockwise rotation of wave direction along the Chilean coast under the climate change scenario. Meanwhile, the ENSO scenarios under cold conditions generated a ETC track's displacement toward the north, causing both an increase in wave height along the coast of the Antofagasta and Atacama regions and a decrease in wave height in the Valparaíso, O'Higgins, and Maule regions. Findings from this study emphasize the importance of considering dynamic design for coastal structures rather than traditional methods to adapt to changing storm patterns. [ABSTRACT FROM AUTHOR]

Coastal storms can cause erosion and flooding of coastal areas, often accompanied by significant social-economic disruption. As such, storm characterisation is crucial for an improved understanding of storm impacts and thus for coastal management. However, storm definitions are commonly different between authors, and storm thresholds are often selected arbitrarily, with the statistical and meteorological independence between storm events frequently being neglected. In this work, a storm identification algorithm based on statistically defined criteria was developed to identify independent storms in time series of significant wave height for high wave energy environments. This approach proposes a minimum duration between storms determined using the extremal index. The performance of the storm identification algorithm was tested against the commonly used peak-over-threshold. Both approaches were applied to 40 and 70-year-long calibrated wave reanalyses datasets for Western Scotland, where the intense and rapid succession of extratropical storms during the winter makes the identification of independent storm events notably challenging. The storm identification algorithm provides results that are consistent with regional meteorological processes and timescales, allowing to separate independent storms during periods of rapid storm succession, enabling an objective and robust storm characterisation. Identifying storms and their characteristics using the proposed algorithm allowed to determine a statistically significant increasing long-term trend in storm duration, which contributes to the increase in storm wave power in the west of Scotland. The coastal storm identification algorithm is found to be particularly suitable for high-energy, storm-dominated coastal environments, such as those located along the main global extratropical storm tracks. [ABSTRACT FROM AUTHOR]

The beach–foredune system at Bengello Beach has been monitored monthly to bimonthly at four profiles (P1–P4) since 1972 and documented the building of a foredune. This paper addresses the remarkable changes which occurred in 2022 as storm waves overtopped and trimmed this foredune at all profiles, then later removed this entire feature at two of the profiles (P3, P4) but not the others (P1, P2). Wave parameters for these storm events, measured by deepwater and nearshore wave buoys, enable a comparison of storm characteristics and resulting beach–foredune impact. During the storm event which destroyed the foredune, nearshore wave height exceeded deepwater wave height, in contrast with other storms that year. The beach–foredune lost 78 m3/m in 2022 and the notable 1974 storms that impacted this coastline resulted in 95 m3/m volume loss. During 2023, beach recovery has occurred, but not rebuilt the foredune. It had persisted for ~40 years enduring many other severe storm events, and the coastal protection afforded by the dune system has been compromised. This highlights the need to consider dune morphology in assessments of erosion hazard and inundation risk along similar coastlines.

Several coastal barriers experienced significant erosion and change in shape throughout the Mediterranean coasts over the past decades, and the issue has become of increasing concern for scientists and policymakers. With reference to a case study and by meteorological and geomorphological investigations, this note aims to define the wind–wave conditions, infer the net longshore transport, and detect the geomorphological processes that shape the landforms of the Cesine Lagoon barrier (South Italy). Despite the importance of the site in coastal defense and environmental conservation, there are still no specific studies. A challenge for this research was to obtain significant results from publicly available sources and simple and inexpensive methods. Geomorphological changes, such as the retreat of dune toes, accretion of washover fans, and formation of gravel beaches, are related to the analyzed wind–wave conditions. The net longshore transport is found in accordance with the direction of the more intense winds. The role of extreme events in the shaping of coastal landforms is yet to be established, even if they greatly increase the vulnerability to flooding of the study area. The results achieved so far are starting points for further data collection and analysis in the perspective of assessing the impact of climate changes and the threatening hazards on the lagoon barrier. [ABSTRACT FROM AUTHOR]

In this review, the potential of an emerging field of interdisciplinary climate research, Coastal Boulder Deposits (CBDs) as natural archives for intense storms, is explored with particular reference to the Mediterranean region. First, the identification of the pertinent scientific articles was performed by the using Web of Science (WoS) engine. Thus, the selected studies have been analysed to feature CBDs produced and/or activated during the last half-century. Then, the meteorological events responsible for the literature-reported cases were analysed in some detail using the web archives of the Globo-Bolam-Moloch model cascade. The study of synoptical and local characteristics of the storms involved in the documented cases of boulder production/activation proved useful for assessing the suitability of selected sites as geomorphological storm proxies. It is argued that a close and fruitful collaboration involving several scientific disciplines is required to develop this climate research field. [ABSTRACT FROM AUTHOR]

This study presents a detailed analysis of changes in wind and wave climate in the Western Mediterranean Sea (WMed), based on 41 years of accurate wind and wave hindcasts. The purpose of this research is to assess the magnitude of recent changes in wave climate and to locate the coastal areas most affected by these changes. Starting from the Theil-Sen slope estimator and the Mann Kendall test, trends in mean and Max significant wave heights (SWH) and wind speed (WS) are analysed simultaneously on seasonal and annual scales. Thus, the new wave records observed since 2010 have been located spatially and temporally using a simple spatial analysis method, while the increases in maximum wave heights over the last decade have been estimated and mapped. This work was motivated by evidence pointed out by several authors concerning the influence of global climate change on the local climate in the Mediterranean Sea and by the increase in the number and intensity of wave storm events over recent years. Several exceptional storms have recently been observed along the Mediterranean coasts, including storm Adrian in 2018 and storm Gloria in 2020, which resulted in enormous damage along the French and Spanish coasts. The results of the present study reflect a worrying situation in large part of the WMed coasts. Most of the WMed basin experiences a significant increasing trend in the annual Max of SWH and WS with evident inter-seasonal variability that underlines the importance of multi-scale analysis to assess wind and wave trends. Since 2013, about half of the WMed coastline has experienced records in wave climate, not recorded at least since 1979, and several areas have experienced three successive records. Several WMed coasts are experiencing a worrying evolution of the wave climate, which requires a serious mobilisation to prevent probable catastrophic wave storms and ensure sustainable and economic development. [ABSTRACT FROM AUTHOR]

The Atlantic Coast of the United States is subjected to damage from wind and flooding as a result of coastal storms. This paper seeks to model the joint probability of exceedance for wind speed and flood elevation, two common measures of storm severity, using the storm data provided by the North Atlantic Coast Comprehensive Study. A case study is performed for Boston, Massachusetts. A copula is used to model the dependence between storm severity measures. The Gaussian copula and the Archimedean copulas (i.e., Gumbel, Clayton, and Frank) are examined in this paper. The correlation matrix used to construct the Gaussian copula is estimated empirically, and the parameters of the Archimedean copulas are estimated by a semi-parametric estimation method. The Gumbel copula, which is found to describe the dependence between the severity measures better than other copulas, is used to develop a copula-based joint probability model. The methodology presented in this paper is used to estimate joint hazard curves for wind speed and flood elevation for different mean recurrence intervals. The results can be used to define hazard scenarios in a multihazard study, estimate building performance under coastal storms, and assess community resilience. [ABSTRACT FROM AUTHOR]

Remote sensing can be helpful in defining the dynamic of a high-latitude coastal environment where the role of cryogenic processes like sea-ice or permafrost are the main drivers together with storm surge and wind action. Here we examined the geomorphological dynamics of a beach located at Edmonson Point (74° S) not far from the Italian Antarctic Station “Mario Zucchelli” between 1993 and 2019 using different remote sensing techniques and field measurements. Our data demonstrate that the average rate of surficial increase of the beach (0.002 ± 0.032 m yr−1) was slightly higher than the uplift rate determined by previous authors (0–1 cm yr−1) in case of pure isostatic rebound. However, we suggest that the evolution of EPNB is likely due to the couple effect of vertical uplift and high wave-energy events. Indeed, the coastline accumulation could be related to the subsurface sea water infiltration and annually freezing at the permafrost table interface as aggradational ice as suggested by the ERT carried out in 1996. This ERT suggests the occurrence of saline frozen permafrost or hypersaline brines under the sea level while permafrost with ice occurred above the sea level. The beach also revealed areas that had quite high subsidence values (between 0.08 and 0.011 m yr−1) located in the area where ice content was higher in 1996 and where the active layer thickening and wind erosion could explain the measured erosion rates. Here, we also dated at the late morning of 15 February 2019 coastal flooding and defined a significant wave height of 1.95 m. During the high oceanic wave event the sea level increased advancing shoreward up to 360 m, three times higher than the previous reported storm surge (81 m) and with a sea level rise almost five times higher than has been previously recorded in the Ross Sea.

To understand why coastal residents do not always evacuate before storms, a pair of studies analyzed evacuation decision-making among residents of Long Beach, NY and surrounding municipalities on Long Island, NY via a mixed methodology approach. First, residents who lived in Long Beach, NY during ‘Superstorm’ (hurricane turned post-tropical cyclone) Sandy in October 2012 were interviewed about their evacuation decision. Second, 34 pre-storm messages were developed and administered to residents of the same area: faced with a hypothetical oncoming hurricane, respondents indicated after each message whether they would evacuate. In the interviews, residents spoke more about friends and family than traditional authority figures; survey results, however, imply that residents are more likely to evacuate given messages from traditional authority figures. This can be resolved with the Elaboration Likelihood Model of persuasion, which suggests that motivation and emotional state influence information processing. Implications for actual emergency message formation are discussed. [ABSTRACT FROM AUTHOR]

Coastal management often relies on large-scale flood mapping to produce sea level rise assessments where the storm-related surge is considered as the most important hazard. Nearshore dynamics and overland flow are also key parameters in coastal flood mapping, but increase the model complexity. Avoiding flood propagation processes using a static flood mapping is less computer-intensive, but generally leads to overestimation of the flood zone, especially in defended urban backshore. For low-lying communities, sea level rise poses a certain threat, but its consequences are not only due to a static water level. In this paper, the numerical process-based model XBeach is used in 2D hydrodynamic mode (surfbeat) to reproduce an observed historical flood in Maria (eastern Canada). The main goal is to assess the impacts of a future storm of the same magnitude in the horizon 2100 according to an increase in sea level rise. The model is first validated from in situ observations of waves and water levels observed on the lower foreshore. Based on field observations of a flood extent in 2010, the simulated flooded area was also validated given a good fit (59%) with the actual observed flood. Results indicate that the 2010 storm-induced surge generated overwash processes on multiple areas and net landward sediment transport and accumulation (washover lobes). The flood was caused by relatively small nearshore waves (Hs < 1 m), but despite small water depth (>1.2 m), high flow velocities occurred in the main street (U > 2 m/s) prior to draining in the salt marsh. The impact of sea level rise on the low-lying coastal community of Maria could induce a larger flood area in 2100, deeper floodwater, and higher flow velocities, resulting in higher hazard for the population.

The highly urbanized estuary of San Francisco Bay is an excellent example of a location susceptible to flooding from both coastal and fluvial influences. As part of developing a forecast model that integrates fluvial and oceanic drivers, a case study of the Napa River and its interactions with the San Francisco Bay was performed. For this application we utilize Delft3D-FM, a hydrodynamic model that computes conservation of mass and momentum on a flexible mesh grid, to calculate water levels that account for tidal forcing, storm surge generated by wind and pressure fields, and river flows. We simulated storms with realistic atmospheric pressure, river discharge, and tidal forcing to represent a realistic joint fluvial and coastal storm event. Storm conditions were applied to both a realistic field-scale Napa river drainage as well as an idealized geometry. With these scenarios, we determine how the extent, level, and duration of flooding is dependent on these atmospheric and hydrologic parameters. Unsurprisingly, the model indicates that maximal water levels will occur in a tidal river when high tides, storm surge, and large fluvial discharge events are coincident. Model results also show that large tidal amplitudes diminish storm surge propagation upstream and that phasing between peak fluvial discharges and high tide is important for predicting when and where the highest water levels will occur. The interactions between tides, river discharge, and storm surge are not simple, indicating the need for more integrated flood forecasting models in the future.

High magnitude coastal storms have persistently threatened human communities and environments. In the British Isles their frequency and magnitude are predicted to increase in the future with advancing climate change. This study analyses sedimentological evidence from south-west Wales to assess the impacts of high magnitude coastal storms in vulnerable coastal saltmarshes in the Three Rivers Estuarine Complex, Carmarthen Bay. Storm surge saltmarsh deposits were identified following geochemical and particle size analyses and dated using radionuclides 137Cs and 210Pb. The sedimentological evidence is compared with regional tidal gauge and meteorological records to assess variability in storm recording and corroborate the storms which produced the sedimentological deposits. Three episodes of high magnitude saltmarsh storm surge deposition are identified in 1954, 1977 and 1981. Evidence of storm erosion or alternative forms of storm deposition were not present. The sedimentological evidence highlights the comparative rarity of major depositional events in the saltmarshes between 1929 and 2019. The recorded depositional events combined with organic accretion have contributed to maintaining saltmarsh elevation relative to sea level. There remains uncertainty surrounding the storm impacts on the saltmarshes of the Three Rivers Estuarine Complex. When the future 21st century threats of increasing regional atmospheric storminess and sea level rise are considered along with predictions of saltmarsh degradation, this study suggests further research is required to explore the sedimentological storm impacts. This could contribute to sustaining the vulnerable coastal saltmarsh environments and the important ecosystem services they provide. [Display omitted] • Major storm surge deposits from 1954, 1977 and 1981, are identified in the saltmarshes of the Three Rivers Estuarine Complex. • Major storm surge deposition occurs sporadically on a multi-decadal timescale between 1929 and 2019. • Regional tidal and meteorological storm records show depositional evidence of storms is comparatively rare. • Organic accretion and storm surge deposition have enabled the saltmarshes to keep pace with relative sea level rise. • Given the predicted regional climate change in the 21st century, saltmarsh sustainability should be monitored. [ABSTRACT FROM AUTHOR]

Remote sensing can be helpful in defining the dynamic of a high-latitude coastal environment where the role of cryogenic processes like sea-ice or permafrost are the main drivers together with storm surge and wind action. Here we examined the geomorphological dynamics of a beach located at Edmonson Point (74° S) not far from the Italian Antarctic Station "Mario Zucchelli" between 1993 and 2019 using different remote sensing techniques and field measurements. Our data demonstrate that the average rate of surficial increase of the beach (0.002 ± 0.032 m yr−1) was slightly higher than the uplift rate determined by previous authors (0–1 cm yr−1) in case of pure isostatic rebound. However, we suggest that the evolution of EPNB is likely due to the couple effect of vertical uplift and high wave-energy events. Indeed, the coastline accumulation could be related to the subsurface sea water infiltration and annually freezing at the permafrost table interface as aggradational ice as suggested by the ERT carried out in 1996. This ERT suggests the occurrence of saline frozen permafrost or hypersaline brines under the sea level while permafrost with ice occurred above the sea level. The beach also revealed areas that had quite high subsidence values (between 0.08 and 0.011 m yr−1) located in the area where ice content was higher in 1996 and where the active layer thickening and wind erosion could explain the measured erosion rates. Here, we also dated at the late morning of 15 February 2019 coastal flooding and defined a significant wave height of 1.95 m. During the high oceanic wave event the sea level increased advancing shoreward up to 360 m, three times higher than the previous reported storm surge (81 m) and with a sea level rise almost five times higher than has been previously recorded in the Ross Sea. [ABSTRACT FROM AUTHOR]

Taking into consideration the changing climate, researchers are mainly interested in measuring this change in many different sectors. Regarding the coastal areas, the effects are related inter alias to the sea level rise, but also the increase and the severity of storms incidence. In conjunction with the astronomical tide, coastal storms can cause extreme wave runup and overtopping phenomena in ports, and coastal structures, the consequences of which may be disastrous, mainly affecting the operation and the reliability of infrastructure. Consequently, the analysis of coastal storms is necessary for any future technical study in coastal engineering, for the design of port and coastal structures and the coastal management also. Coastal storms as multivariate and extreme events necessitate a detailed and multivariate analysis of many parameters. This work aims to review and highlight the most significant issues in coastal storm analysis, to summarise the knowledge and the current trends of coastal storms research, by exploring the scientific background through a literature overview. A guiding framework of storm analysis should include the most important aspects of this work which are: the coastal storm definition, the description of their severity, the understanding of the synoptic systems formation, the storm surges and the time-series analysis, the thresholds for their identification, the impacts, their classification, and finally the impacts of coastal storms on coastal human population. Image 1 • Reviews key research issues of coastal storm analysis. • Presents the recent research trends of coastal storms. • Explores the definition of coastal storms. • Gives prominence to the multifaceted and detailed analysis of coastal storms. [ABSTRACT FROM AUTHOR]

Coastal erosion is driven by both a storm's erosion potential and by an area's vulnerability. Therefore, the problem of estimating impacts can be approached in two-step. The first includes an assessment of erosion potential based on readily available storm parameters, while the second combines this information with highly localized parameters, describing vulnerability, to more directly predict local impacts. The work presented in this paper focuses on this first step, where a storm erosion potential climatology is developed by analyzing historical storms and is then utilized to identify historic patterns. Specifically, storms which have impacted the New Jersey coast over the past several decades are reevaluated using the Storm Erosion Index (SEI), developed by Miller and Livermont (2008), which considers the three primary storm-related drivers of coastal erosion (wave height, water level, and storm duration). These storms are assessed at thirteen shoreline segments defined along New Jersey's Atlantic coast from a 34 year-period (1980–2013) when concurrent wave and water level data is available. Approximately 130 unique storms are identified with the top three being the December 1992 nor'easter, the November 2009 Veteran's Day Storm, and Hurricane Sandy in October 2012, each having an estimated return period of greater than 15 years. The resulting climatology is found to exhibit several interesting spatial and temporal trends. Both portions of the state as well as months of the year that have historically experienced more storms and/or higher cumulative SEI (over the 34 years) are identified. While analysis of the climatology has also identified periods of reduced storm activity and those of intensified conditions, future monitoring is suggested to assess whether these patterns are persistent or related to climatic variations with cycles longer than can be captured by the thirty years included in this study. • SEI is capable of classifying and ranking major storms that have impacted the New Jersey coast based on erosion potential. • Approximately 130 unique storms are identified at each of the thirteen shoreline segments in New Jersey between 1980 2013. • The 34-year climatology is used to identify spatial and temporal patterns in erosion potential for the state. • The coastline towards the middle of the state experiences more storms and more intense storms than the northernmost sections. • By month, October has the highest cumulative SEI due to the number of high intensity storms. [ABSTRACT FROM AUTHOR]

The mainland coast of China is about 18,000 km long and houses about 70% of China's largest cities and 50% of its population. For the last few decades, the rapid growth of the Chinese economy has resulted in extensive development of the coastal infrastructure and property, large-scale expansion of coastal ports, excessive reclamation of coastal land, and a significant increase in the coastal population. Previous studies have indicated that tropical cyclones (TCs) have struck the coast of China at a higher frequency and intensity, and TC-induced coastal hazards have resulted in heavy human losses and huge losses to the Chinese coastal economy. In analyzing the long-term and most recent coastal hazard data collected on the coast of China, this study has found that TC-induced storm surges are responsible for 88% of the direct coastal economic losses, while TC-induced large coastal waves have caused heavy loss of human lives, and that the hazard-caused losses are shown to increase spatially from the north to south, peak in the southern coastal sector, and well correlate to storm wave energy flux. The frequency and intensity of coastal hazards on the coast of China are expected to increase in response to future changing TC conditions and rising sea levels. A simple two-parameter conceptual model is also presented for the assessment of coastal inundation and erosion hazards on the coast of China. [ABSTRACT FROM AUTHOR]

Coastal management often relies on large-scale flood mapping to produce sea level rise assessments where the storm-related surge is considered as the most important hazard. Nearshore dynamics and overland flow are also key parameters in coastal flood mapping, but increase the model complexity. Avoiding flood propagation processes using a static flood mapping is less computer-intensive, but generally leads to overestimation of the flood zone, especially in defended urban backshore. For low-lying communities, sea level rise poses a certain threat, but its consequences are not only due to a static water level. In this paper, the numerical process-based model XBeach is used in 2D hydrodynamic mode (surfbeat) to reproduce an observed historical flood in Maria (eastern Canada). The main goal is to assess the impacts of a future storm of the same magnitude in the horizon 2100 according to an increase in sea level rise. The model is first validated from in situ observations of waves and water levels observed on the lower foreshore. Based on field observations of a flood extent in 2010, the simulated flooded area was also validated given a good fit (59%) with the actual observed flood. Results indicate that the 2010 storm-induced surge generated overwash processes on multiple areas and net landward sediment transport and accumulation (washover lobes). The flood was caused by relatively small nearshore waves (Hs < 1 m), but despite small water depth (>1.2 m), high flow velocities occurred in the main street (U > 2 m/s) prior to draining in the salt marsh. The impact of sea level rise on the low-lying coastal community of Maria could induce a larger flood area in 2100, deeper floodwater, and higher flow velocities, resulting in higher hazard for the population. [ABSTRACT FROM AUTHOR]

The highly urbanized estuary of San Francisco Bay is an excellent example of a location susceptible to flooding from both coastal and fluvial influences. As part of developing a forecast model that integrates fluvial and oceanic drivers, a case study of the Napa River and its interactions with the San Francisco Bay was performed. For this application we utilize Delft3D-FM, a hydrodynamic model that computes conservation of mass and momentum on a flexible mesh grid, to calculate water levels that account for tidal forcing, storm surge generated by wind and pressure fields, and river flows. We simulated storms with realistic atmospheric pressure, river discharge, and tidal forcing to represent a realistic joint fluvial and coastal storm event. Storm conditions were applied to both a realistic field-scale Napa river drainage as well as an idealized geometry. With these scenarios, we determine how the extent, level, and duration of flooding is dependent on these atmospheric and hydrologic parameters. Unsurprisingly, the model indicates that maximal water levels will occur in a tidal river when high tides, storm surge, and large fluvial discharge events are coincident. Model results also show that large tidal amplitudes diminish storm surge propagation upstream and that phasing between peak fluvial discharges and high tide is important for predicting when and where the highest water levels will occur. The interactions between tides, river discharge, and storm surge are not simple, indicating the need for more integrated flood forecasting models in the future. [ABSTRACT FROM AUTHOR]

Hurricane Andrew caused widespread damage to the Acropora palmata population on a patch reef on the Florida Reef Tract. After the storm, more than 50% of the A. palmata cover in the rubble and reef-flat zones was comprised of live fragments. Other species of coral were minimally damaged. Most fragments were distributed within or adjacent to the remaining patches of standing elkhorn colonies. Neither distribution nor mortality rate of fragments was dependent on initial fragment size. However, rate of stabilization of fragments was related to substrate type and distance from a patch of mature colonies, suggesting that standing colonies may protect regenerating fragments from removalfrom the reef. Differences in the substrate type (hard vs. unconsolidated rubble) where fragments landed, affected removal, total mortality, and partial mortality rates of hurricane-generated fragments. Rubble substrate favored stabilization and survival of hurricane-generated asexual recruits. [ABSTRACT FROM AUTHOR]

Climate change may affect the frequency, intensity, and geographic distribution of severe coastal storms. Concurrent sea-level rise wouldraise the baseline of flooding during such events. Meanwhile, socialvulnerability factors such as poverty and disability hinder the ability to cope with storms and storm damage. While physical changes are likely to remain scientifically uncertain into the foreseeable future, the ability to mitigate potential impacts from coastal flooding maybe fostered by better understanding the interplay of social and physical factors that produce human vulnerability. This study does so by integrating the classic causal model of hazards with social, environmental, and spatial dynamics that lead to the differential ability of people to cope with hazards. It uses Census data, factor analysis, data envelopment analysis, and floodplain maps to understand the compound social and physical vulnerability of coastal residents in the cityof Revere, MA, USA. [ABSTRACT FROM AUTHOR]