Storm Surge Events Research Articles

Storm surge along the Pacific coast of North America

AbstractStorm surge is an important factor that contributes to coastal flooding and erosion. Storm surge magnitude along eastern North Pacific coasts results primarily from low sea level pressure (SLP). Thus, coastal regions where high surge occurs identify the dominant locations where intense storms make landfall, controlled by storm track across the North Pacific. Here storm surge variability along the Pacific coast of North America is characterized by positive nontide residuals at a network of tide gauge stations from southern California to Alaska. The magnitudes of mean and extreme storm surge generally increase from south to north, with typically high amplitude surge north of Cape Mendocino and lower surge to the south. Correlation of mode 1 nontide principal component (PC1) during winter months (December–February) with anomalous SLP over the northeast Pacific indicates that the dominant storm landfall region is along the Cascadia/British Columbia coast. Although empirical orthogonal function spatial patterns show substantial interannual variability, similar correlation patterns of nontide PC1 over the 1948–1975 and 1983–2014 epochs with anomalous SLP suggest that, when considering decadal‐scale time periods, storm surge and associated tracks have generally not changed appreciably since 1948. Nontide PC1 is well correlated with PC1 of both anomalous SLP and modeled wave height near the tide gauge stations, reflecting the interrelationship between storms, surge, and waves. Weaker surge south of Cape Mendocino during the 2015–2016 El Niño compared with 1982–1983 may result from changes in Hadley circulation. Importantly from a coastal impacts perspective, extreme storm surge events are often accompanied by high waves.

Ichnofauna record cryptic marine incursions onto a coastal floodplain at a key Lower Mississippian tetrapod site

Ichnofossils from a Lower Mississippian (Tournaisian) coastal plain succession with a rich vertebrate fauna, including early tetrapods, record repeated, short-lived marine interactions that influenced floodplain lake development and ecosystems. The ichnofauna contrasts with the more typical Scoyenia Ichnofacies of other Devonian-Carboniferous tetrapod sites. In the Tournaisian Ballagan Formation of the Scottish Borders, Chondrites is identified in 128 horizons within a 500-m succession and is associated with lesser occurrences of phycosiphoniform burrows, Diplocraterion, Rhizocorallium and Zoophycos?. Chondrites and phycosiphoniform burrows commonly occur within dolostones, interpreted as part of a saline-hypersaline lake facies association, containing a non-marine to marginal marine macrofauna of bivalves, ostracods, Spirorbis, Serpula and sarcopterygian fish. Marine scolecodonts are reported from 18 horizons of diverse lithology, four of which co-occur with Chondrites. The single-colonisation, single-tier, high ichnofabric index and thin beds (mean 10cm thick) that characterise Chondrites horizons indicate: 1) adverse environmental conditions; 2) rapid colonisation of the sediment; and 3) short-lived bioturbation episodes. Other ichnotaxa identified are Monocraterion and Asterosoma?, which occur exclusively within the overbank or fluvial facies associations, and are here interpreted to have lived in freshwater conditions. The Chondrites trace-makers are interpreted as having originated in shallow-marine waters and were transported into floodplain lakes by storm surge events, although a few examples suggest more significant transgressions. Ichnofossils are much more common than marine body fossils or scolecodonts, and thus record cryptic marine incursions that might otherwise remain unidentified. This study contributes to our understanding of the complex mosaic of environments present when terrestrial tetrapods first appeared.

Identification and classification of storm surge events at Red Dog Dock, Alaska, 2004–2014

Powerful storms in the Bering and Chukchi Seas west of Alaska frequently bring high winds that drive positive and negative surge events (storm surges). Positive surge events can cause inundation of coastal regions, extending far inland in low-relief locations. A 10-year record (2004–2014) of water level data from Red Dog Dock located to the north of the Bering Strait on the Alaskan coast was analysed for observed severe surge events. A climatology of events was developed, in which event occurrences were grouped by temporal evolution of the event. The length of time (speed) it took for a given storm system to move over the region largely dictated the temporal evolution of the surge events. The mapped time series evolution of the measured storm surge was grouped into four distinct surge event types. The primary synoptic control on these events is the orientation of the pressure gradient caused by the passage of low-pressure systems. The orientation of the pressure gradient, and therefore dominant wind direction, determine the magnitude, duration, and positive or negative storm surge inundation. The climatology resulted in 44 observed events—21 positive, 23 negative—that tended to occur during the months of November, December, and January. It was also noted that surges also regularly occurred when sea-ice cover was present. The primary synoptic forcing mechanism for positive surges was an extra-tropical cyclone positioned over the North Bering Sea/Chukotka Peninsula area, and for negative surges, an extra-tropical cyclone positioned over the Alaska Peninsula/western Gulf of Alaska.

Storm surge vulnerability assessment of Saurashtra coast, Gujarat, using GIS techniques

The coastal stretch of Saurashtra, Gujarat, is seriously threatened by storm surges. Hence, assessing the preparedness to storm surge impacts is a major task in coastal disaster management where identification of relative vulnerability of coastal stretches is a prime concern. The aim of this study is to assess coastal vulnerability related to storm surge events along the coastal talukas of Saurashtra coast, by analyzing physical features and demographic variables using Geographical Information System (GIS) techniques. Vulnerability of a taluka is defined in terms of its exposure, sensitivity, and adaptive capacity. We calculated vulnerability of Exposure Index, Sensitivity Index, and Adaptive Capacity Index separately in ArcMap s/w, and the vulnerability map of different indices in the study region was drawn. The Total Vulnerability Index (TVI) is prepared by integrating the above index. The TVI map shows that Kalyanpur, Porbandar, and Talaja talukas are highly vulnerable in comparison with other talukas as they have large area under low-lying, high sensitivity value, and low adaptive capacity value. On the other hand, Diu and Maliya are lower vulnerable due to the presence of rocky/cliffy coast, sand dune, small coastal length and located in elevated region although there exists high population density and built-up area. Our research finding will assist coastal disaster managers and decision makers to plan appropriate measures to minimize the losses due to storm surge impacts.

Numerical investigation of surge–tide interactions in the Bay of Bengal along the Bangladesh coast

The tidal amplitude at the Bay of Bengal along the Bangladesh coast varies from 2 to 7 m, whereas the tidal phase differs by more than 3 h from the outer part toward the inner part of the Meghna Estuary. At the time of cyclone landfall, the tidal phase has a significant impact on surge height, arrival time and duration. In this paper, the nature of surge–tide interactions at the Bay of Bengal along the Bangladesh coast has been investigated using a two-dimensional nonlinear shallow water model coupled with a storm surge model. Two previous major storm surge events along the Bangladesh coast have been analyzed for surge–tide interaction: Cyclone 1991 and Cyclone Sidr in 2007. To investigate the impact of the tidal phase on surge characteristics, in addition to the base cases, storm surges have been calculated at different phases of an entire tidal cycle at 1-h intervals. The results indicate that during the ebb tides the calculated total surge height of the surge–tide interaction model was higher compared to the total surge height obtained by superimposing surge height that is separately calculated with mean water level over the local tidal water level; the opposite occurs during high tide. The surge propagation time toward the inner part of the bay significantly varied depending on the tidal phases. When the tidal water level along the coast was low, the speed of surge propagation was much slower compared with when the tidal water level was high. The surge duration increases when the falling surge profile encounters an opposing strong tidal current at the landfall location.

Spatial and temporal analysis of extreme sea level and storm surge events around the coastline of the UK.

In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915–2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (<4 days) typically impact different stretches of coastline. The spring/neap tidal cycle prevents successive extreme sea level events from happening within 4–8 days. Finally, the 2013/14 season was highly unusual in the context of the last 100 years from an extreme sea level perspective.

Climate change effects on the marine characteristics of the Aegean and Ionian Seas

This paper addresses the effects of estimated climate change on the sea-surface dynamics of the Aegean and Ionian Seas (AIS). The main aim is the identification of climate change impacts on the severity and frequency of extreme storm surges and waves in areas of the AIS prone to flooding. An attempt is made to define design levels for future research on coastal protection in Greece. Extreme value analysis is implemented through a nonstationary generalized extreme value distribution function, incorporating time harmonics in its parameters, by means of statistically defined criteria. A 50-year time span analysis is adopted and changes of means and extremes are determined. A Regional Climate Model (RegCM3) is implemented with dynamical downscaling, forced by ECHAM5 fields under 20C3M historical data for the twentieth century and the SRES-A1B scenario for the twenty-first century. Storm surge and wave models (GreCSSM and SWAN, respectively) are used for marine climate simulations. Comparisons of model results with reanalysis and field data of atmospheric and hydrodynamic characteristics, respectively, are in good agreement. Our findings indicate that the dynamically downscaled RegCM3 simulation adequately reproduces the present general circulation patterns over the Mediterranean and Greece. Future changes in sea level pressure and mean wind fields are estimated to be small, yet significant for marine extremes. In general, we estimate a projected intensification of severe wave and storm surge events during the first half of the twenty-first century and a subsequent storminess attenuation leading to the resettlement of milder extreme marine events with increased prediction uncertainty in the second half of the twenty-first century.

Development of a 3D dynamic flood web GIS visualisation tool

Low elevation coastal areas are vulnerable to the effects of sea level rise and to an increase in the frequency and severity of storm surge events due to climate change. Coastal urban areas are at risk because coastal flooding causes extensive damage to energy and transportation infrastructure, disruptions to the delivery of services, devastating tolls on the public's health and, occasionally, significant loss of life. Although scientists widely stress the compelling need to mitigate and adapt to climate change, public awareness lags behind. Because WebGIS maps (web-based geographic information systems) quickly convey strong messages, condense complex information, engage people in issues of environmental change, and motivate personal actions, this paper focusses on searching the ideal flood assessment WebGIS method to encourage people to mitigate and adapt to climate change. Surveys demonstrated that 3D visualisations have an enormous added value because they are more vivid and therefore more understandable and make it easier to imagine the consequences of a flood than 2D visualisations. In this research, the WebGIS will be created using Ol3-Cesium and open layers to visualise a flood event by dynamic layers in a 2D/3D environment.

Developing a theoretical framework for integrated vulnerability of businesses to sea level rise

Sea level rise (SLR), as a likely outcome of climate change, threatens coastal communities through intensified storm surge, strong wind, flooding, and other extreme weather events. While social vulnerability to SLR is receiving overwhelming attention from research communities, studies on the business impacts of SLR are much less developed. In this study, an innovative framework of integrated business vulnerability is developed for environmental hazards (e.g., SLR) and is validated by a case study of Bay County, Florida. First, the model establishes a composite business vulnerability index (BVI) by incorporating business characteristics, infrastructure factors, and other indicators based on existing literature results. Second, it identifies impacted business indicators and how they will change with the projected SLR. To account for climate change uncertainty, floodplains are generated under three SLR levels (0, 0.2, and 0.9 m). Finally, this study uses a GIS-based methodology to combine physical and business vulnerabilities to investigate overall susceptibility and how this changes with SLR. Two important findings are identified. First, business vulnerability to flooding will be escalated substantially by SLR. Considerable amount of areas, businesses, and road networks would be exposed to highest flood risk zones due to SLR. Second, highest flood risk zones do not necessarily intersect with those areas of high BVI. The results can help local governments better allocate financial and manpower resources and assist hazard mitigation teams, urban planners, and city managers in steering business development away from high-risk regions due to SLR.

A storm surge forecasting system for the Singapore Strait

AbstractBeing a small low-lying island nation, Singapore has a high density population, recreational and industrial facilities along the coast. It is thus highly vulnerable to weather extremes including storm surges. Strong sea level surges due to the northeast monsoon when coinciding with spring tides may lead to coastal floods in the southwest regions of the South China Sea including Singapore Strait, with the heights of about 0.3-0.5 m observed from tidal records and satellite altimetry. We developed an operational system codenamed “Stormy” to provide storm surge forecasts for the Sunda Shelf with focus on the Singapore Strait for a lead time of 6–7 days. Stormy has been working operationally since February 2013, successfully capturing storm surge events on 19–30 December 2013 and 14–23 February 2014. Stormy’s web-based portal has an intuitive visual user interface which conveniently offers forecast products, including evolutional plan-view and time-series of storm surge heights compared with historical anomalies.

Adjoint free four-dimensional variational data assimilation for a storm surge model of the German North Sea

In this paper, a data assimilation scheme based on the adjoint free Four-Dimensional Variational(4DVar) method is applied to an existing storm surge model of the German North Sea. To avoid the need of an adjoint model, an ensemble-like method to explicitly represent the linear tangent equation is adopted. Results of twin experiments have shown that the method is able to recover the contaminated low dimension model parameters to their true values. The data assimilation scheme was applied to a severe storm surge event which occurred in the North Sea in December 5, 2013. By adjusting wind drag coefficient, the predictive ability of the model increased significantly. Preliminary experiments have shown that an increase in the predictive ability is attained by narrowing the data assimilation time window.

Assessing Future Flood Hazards for Adaptation Planning in a Northern European Coastal Community

From a transdisciplinary approach in the town of Thyboron, Denmark, we investigate couplings between sea state (i.e. mean and extreme) and flooding hazards today and ahead. This includes analyses of change and variability in the groundwater table, precipitation, land motion, geotechnical ground properties, sewerage systems and other infrastructure to outline a more complete platform for the integration of knowledge into climate adaptation schemes at this highly vulnerable coastal location. It involves the engagement of the main stakeholders who, although having different responsibilities, interests, needs of knowledge and data, and different timeframes for investment and planning, must join in a common appraisal of the challenges faced ahead to provide for better adaptation measures. Apart from obvious adverse effects from future storm surge events, knowledge about the coupled effects of the abovementioned parameters needs to be taken into account to reach optimal mitigation and adaptation measures. Through stakeholder interviews it becomes clear that an enhanced focus on transdisciplinary research is a viable way forward to develop such measures: it will bring in more knowledge, a broader scope, and it will provide for more holistic solutions that both serve to protect the town and allow for business development and better municipal planning ahead.

Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

Abstract. Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time-mean sea level were evaluated using the process-based climate model data and methods presented in the United Nations Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Regional surge and wave solutions extending from 1980 to 2100 were generated using ∼ 12 km resolution surge (Nucleus for European Modelling of the Ocean – NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled ( ∼ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980 to 2010, enabling a quantitative assessment of model skill. Simulated historical sea-surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data, respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the Representative Concentration Pathway (RCP)4.5 (8.5) scenarios. Trends in surge and significant wave height 2-year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of ∼ 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region.

Mudanças de curto prazo no balanço sedimentar da Praia do Icaraí (Caucaia, Ceará) durante uma ressaca do mar

Este artigo apresenta resultados de um experimento de campo realizado para avaliar a resposta morfológica de uma praia arenosa durante um evento de ressaca do mar. O estudo foi realizado na Praia do Icaraí, localizada no litoral da Região Metropolitana de Fortaleza. O experimento de campo foi baseado no acompanhamento contínuo de cinco seções de controle a partir de informações topográficas e oceanográficas. Foram realizadas 7 campanhas de campo (28/01/14 a 09/02/14). As respostas morfológicas dos trechos observados foram diferentes em termos de erosão e deposição. A seção limitada por dunas antropizadas (S1) apresentou erosão da berma e da praia submersa. Os trechos costeiros limitados por uma estrutura de proteção costeira (S2 a S4) apresentaram recuo da parte superior do perfil. No trecho de dunas frontais (S5), houve uma erosão generalizada da duna e da berma. De forma geral, a Praia do Icaraí é vulnerável a eventos de ressaca do mar.

Shelfbreak current over the Canadian Beaufort Sea continental slope: Wind‐driven events in January 2005

AbstractThe shelfbreak current over the Beaufort Sea continental slope is known to be one of the most energetic features of the Beaufort Sea hydrography. In January 2005, three oceanographic moorings deployed over the Canadian (eastern) Beaufort Sea continental slope simultaneously recorded two consecutive shelfbreak current events with along‐slope eastward bottom‐intensified flow up to 120 cm s−1. Both events were generated by the local wind forcing associated with two Pacific‐born cyclones passing north of the Beaufort Sea continental slope toward the Canadian Archipelago. Over the mooring array, the associated westerly wind exceeded 15 m s−1. These two cyclones generated storm surges along the Beaufort Sea coast with sea surface height (SSH) rising up to 1.4 m following the two westerly wind maxima. We suggest that the westerly along‐slope wind generated a surface Ekman onshore transport. The associated SSH increase over the shelf produced a cross‐slope pressure gradient that drove an along‐slope eastward geostrophic current, in the same direction as the wind. This wind‐driven barotropic flow was superimposed on the background baroclinic bottom‐intensified shelfbreak current that consequently amplified. Summer‐fall satellite altimetry data for 1992–2013 show that the SSH gradient in the southeastern Beaufort Sea is enhanced over the upper continental slope in response to frequent storm surge events. Because the local wind forcing and/or sea‐ice drift could not explain the reduction of sea‐ice concentration over the Beaufort Sea continental slope in January 2005, we speculate that wind‐driven sea level fluctuations may impact the sea‐ice cover in winter.

Storm surge evolution and its relationship to climate oscillations at Duck, NC

Coastal communities experience increased vulnerability during storm surge events through the risk of damage to coastal infrastructure, erosion/deposition, and the endangerment of human life. Policy and planning measures attempt to avoid or mitigate storm surge consequences through building codes and setbacks, beach stabilization, insurance rates, and coastal zoning. The coastal emergency management community and public react and respond on shorter time scales, through temporary protection, emergency stockpiling, and evacuation. This study utilizes time series analysis, the Kolmogorov-Smirnov (K-S) test, Pearson’s correlation, and the generalized extreme value (GEV) theorem to make the connection between climate oscillation indices and storm surge characteristics intra-seasonally to inter-annually. Results indicate that an El Nino (+ENSO), negative phase of the NAO, and positive phase of the PNA pattern all support longer duration and hence more powerful surge events, especially in winter. Increased surge duration increases the likelihood of extensive erosion, inland inundation, among other undesirable effects of the surge hazard.

Effect of Large-Scale Atmospheric Circulation and Wind on Storm Surge Occurrence

ABSTRACT Montreuil, A-L.; Elyahyioui, J., and Chen, M., 2016. Impact of local wind and atmospheric circulation patterns on coastal morphological changes along the Belgian coast. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 755–759. Coconut Creek (Florida), ISSN 0749-0208. Large scale atmospheric circulation is an important component of wind forcing which in turn control strom surge generation. The study aim is to evaluate the impact of large-scale atmospheric flow and wind on the occurrence of storm surges causing significant morphological impacts along the Belgian coast. An objective classification scheme of the atmospheric circulation affecting the North Sea basin is used for almost 150-years (1871–2014). The observed storm surge events associated with erosion are examined with respect to the circulation weather types (CWTs) and the winter No...

Effect of Fluctuating Salinity on Potential Denitrification in Coastal Wetland Soil and Sediments

The coastal wetlands of southern Louisiana provide an ideal environment for removing nitrate (NO₃⁻) from the Mississippi River before discharge into the Gulf of Mexico where it can contribute to hypoxia. However, denitrification, the primary mechanism of excess N removal, may be sensitive to the fluctuating salinities that characterize coastal wetlands. Salinity can shift from salt to fresh during river inflows, or from fresh to salt during storm surge events. This study investigated the impact of shifting salinity on potential denitrification rates in marsh soils and bayou sediments from the fresh and salt marshes of Brenton Sound estuary. Potential denitrification rates were quantified using bottle incubations for both short-term (2 d), and longer-term (11 d) studies. Fresh marsh sites had higher denitrification enzyme activity (DEA), but all soils and sediments achieved high denitrification when exposed to ideal conditions. Pulses of freshwater (0 ppt) in salt marsh soils decreased potential denitrification rates by 98% for an 11-d study, indicating the rapid opening of a freshwater diversion could significantly reduce that ability of coastal wetlands to provide significant nutrient-removal before discharge to the coastal ocean. Pulses of intermediate salinity (15 ppt) water stimulated denitrification rates in the fresh marsh soil by 75%, while full salinity seawater (35 ppt) suppressed potential denitrification by 73% for 11 d. This research demonstrates the sensitivity of the denitrifying microbial consortia to rapid shifts in salinity and this information can be used to guide water managers on maximizing NO₃⁻ removal in Mississippi River surface water diversions.

Storm Surge Impact to Subterranean Areas by Hurricane Sandy, and Lessons for Japan’s Storm Surge Countermeasures

Hurricane Sandy caused critical damage to subterranean infrastructure in New York and also claimed 285 human lives across the Eastern Seaboard. The storm surge impact easily overwhelmed existing pumping systems, devastating power supply and paralyzing transport. Despite extensive preparations and pre-storm public information efforts, inundation and underground flooding caused causalities. The size of the disaster, sheer scope of damage and multifaceted response spanning the onset through to the recovery phase provides useful lessons for Japan, given its vulnerability to similar storm surges and flooding disasters, such as the Ise Bay Typhoon of 1959. Given this, a delegation composed of members of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and Researchers from Japan’s Universities and Academic Societies working in disaster prevention conducted two surveys in 2013 and 2014. This involved hearing from emergency management officers in New York, Washington D.C and coastal communities about their experiences evacuating vulnerable residents and protecting critical infrastructure. The author of this paper was a member of both delegations. Based on fieldwork from these joint surveys and other materials, this paper outlines the scope of the damage that a storm of Sandy’s size was capable of inflicting, and looks at lessons applicable to Japan for preventing similar damage to infrastructure and human life in future storm surge events, and discusses how New York is attempting to become a more resilient city in preparation for the next flooding or storm surge disaster.

Storm surge modelling in Venice: two years of operational results

ABSTRACTSea-level forecasting in Venice is a fundamental task for safeguarding the ancient city, its cultural heritage and natural environment. In the last 10 years the finite-element numerical Shallow Water Hydrodynamic Model (SHYFEM), developed at the Institute of Marine Sciences (ISMAR) of the National Research Council (CNR) of Venice, has been operationally implemented at the Istituzione Centro Previsioni e Segnalazioni Maree (ICPSM) forecast centre of the Venice Municipality. The model calculates sea level and currents in the whole Mediterranean Sea and the Venice Lagoon under the action of atmospheric forcing fields (pressure and winds) operationally supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF). A neural-network module was implemented to correct model results with observed sea-level data in the Adriatic Sea. Every 6 h, the operational model produces a sea-level forecast for the next six days in the Northern Adriatic Sea in the Venice Lagoon. A statistical analysis was performed on the operational results for 2008–2009, to investigate the model goodness-of-fit and its reliability in the operational context. The main statistical quantities (mean error Ē, standard deviation σ, maximum overestimation Emax and maximum underestimation Emin) were computed. The model predicts the sea level both in Venice and in the open sea with good accuracy, with Ē and σ of the order of 1 cm and 5 cm, respectively, in the first 24 h of anticipation during normal weather conditions. Model errors increase when only considering periods of storm surge events.