Rip Currents Research Articles

Investigations-based results on the hydrographic conditions with special reference to the tourist bathing areas of the protected Romanian littoral

The aim of the present work is related to the new hydrographic conditions within newly developed coastal areas through coastal protection measures extension. The study also seeks to assess the impact on the touristic bathing areas and its safety. The new bathymetry, induced by the sediment size, together with currents propagation into the bathing areas adjacent to the newly arranged beach areas were subject of Conductivity Temperature and depth profiler (CTD) and Acoustic Doppler Current Profiler (ADCP) measurements in relation to the summer waves regime and sea level variations. Several experiments habitually conducted during the summer period were considered; the experiments are related to the marine hazards associated to the swimming areas, such as seasonal storm-inducing currents and the propagation of the rip currents in the nearshore, but also to the specific marine currents setups around beach protection groins and longitudinal breakwater, the influence of vertical water movements, including up-welling and specific intensifications in the periods with complex stormy waves.

Conoce Tus Opciones: The Challenges of Communicating Rip Current Information in Spanish

Abstract Rip currents are poorly understood by the public and thus a leading cause of weather-related fatalities in the United States. Individuals who speak languages other than English, such as Spanish-speaking communities, have been historically underserved by communication efforts for natural hazards and thus are at additional risk from rip currents. In response, the National Weather Service (NWS) has developed rip current outreach tools translated into Spanish in recent years, though their efficacy has not been systematically tested. We therefore surveyed members of the Spanish-speaking community in the New York City area to gain insights into how the NWS two-page rip current informational brochure is working and possible improvements to be made. The English version of the brochure was also tested, and the results from the two languages were compared. Quantitative survey results indicate that while both brochures are generally effective, several changes could be made to improve clarity, especially for Spanish speakers, who found more issues with the Spanish version. For example, the translation of the term rip current itself used by the NWS, “corrientes de resaca,” was determined to be confusing by some Spanish speakers, as were other pieces of text with complex scientific terms. Moreover, certain graphics contained in the brochure were difficult to understand for users in both languages. The results of this work can be used by the NWS and other agencies to improve their Spanish risk communication tools and can also be used as a guide when translating scientific information into other languages. Significance Statement Rip currents, narrow channels of fast-moving water that can pull swimmers away from the shore, are among the leading weather-related killers in the United States yet are poorly understood by the public. Recent efforts to reduce society’s vulnerability to rip currents include the translation of outreach materials from English to Spanish. This study evaluated a new National Weather Service Spanish rip current informational brochure and compared it to the English version. The results show that while both the English and Spanish brochures were generally effective at communicating risk, the Spanish version had more issues, primarily surrounding the translation of scientific terms and phrases. Findings from this research can help guide scientists in designing improved non-English severe weather outreach products.

Modeling Rip Current Systems around Multiple Submerged Breakwaters

Multiple submerged breakwaters (MSBWs) are commonly used coastal protection structures due to their specific advantages over the emerged ones. Rip currents, as the inevitable natural hazard in the gaps of these constructions, are investigated numerically in the present study. A fully nonlinear mild-slope equation (NMSE) model possessing both fully nonlinear and fully dispersive properties is validated and adopted in the simulations. With four monochromatic wave conditions of different wave heights, periods and incidences representing low-energy, typical, storm and oblique waves tested, the flow patterns and the low-frequency oscillations of the rip currents are studied. For the convenience of risk assessment, the rip risk level is divided into three degrees according to the maximum rip flow speed. The effects of the configurations of the MSBWs on the rip current system as well as the rip risk level are examined, considering different breakwater widths, heights, forms, gap widths and gap numbers. Simulation results suggest that the cross-shore configurations of MSBWs influence the rip risk level by inducing different wave energy dissipations but the longshore configurations of MSBWs by changing flow field patterns.

Flow characteristics of the rip current system adjacent to a coastal vertical structure for irregular waves

Rip currents are common hazards found on many beaches around the world. The present research examines the rip current flow features adjacent to a coastal vertical structure with total reflection function to the incident waves. The laboratory experiments were conducted over the planar beach for both regular and irregular waves to explore the specific phenomenon for the irregular waves, and a higher-order Boussinesq equation model was adopted in the simulations to analyze the formation mechanism of the flow features. The study results show that, the standing wave pattern for the irregular wave is much weaker than that for the regular wave with inducing only one apparent node rip at the first node line in the reflection wave area. Moreover, the specific “single-vortex” flow pattern was formed in the crossing wave field for the irregular wave tests. This specific flow pattern is found essentially induced by the larger wave reflection rate of the vertical structure, which leads to the strong lateral flow against the downstream longshore current. This specific flow pattern prefers to present for the smaller wave incident angles and larger wave heights and periods, and leads to the feeding flow volume rates discharged more in the form of lateral flow. The C-shaped lateral flow is found mainly induced by the longshore gradient of the wave set-up instead of the non-uniform wave radiation stress nearshore.

Numerical investigation of rip currents near a barred beach induced by irregular waves

Rip currents pose a common natural hazard at coastal tourist beaches, presenting a significant threat to the safety of beachgoers and beach management. To better understand the characteristics of rip currents, particularly those induced by irregular waves on a barred beach, this study utilized a Boussinesq-type, phase-resolving hydrodynamic model for numerical simulations. We investigated various factors, including significant wave height, peak period, incident angle, and bottom friction, to assess their impact on rip currents formation. The results of our research reveal some key insights. Firstly, an increase in significant wave height and peak period fosters the development of rip currents. However, beyond a certain threshold, the intensity of the rip currents decreases. Conversely, a larger incident angle tends to reduce the intensity of rip currents. Additionally, higher bottom friction leads to increased energy dissipation during wave propagation, consequently resulting in decreased rip currents intensity. In an effort to create a more precise representation of real sea conditions, multi-directional waves were employed as incident waves in this study. An analysis of different standard deviations of directional distributions revealed that as the directional spread of incident waves widens, the waves become more susceptible to breaking, ultimately leading to a reduction in the intensity of rip currents.

Public awareness of rip currents among American adults

AbstractRip current awareness is essential for safety of the beach-going American public. In this study, we investigated American adults’ awareness of ocean safety via an online survey. A total of 1226 respondents participated in the survey. The results revealed that only 44% of the participants were aware that rip currents are the major cause of drownings in the United States. Most participants (64%) reported that the best way to escape a rip current was by swimming parallel (sideways) to the shore, while 8% reported it to be floating and letting the current carry one; further 3% of the respondents mentioned screaming for help as a rescue measure. Interestingly, while most of the respondents reported they could swim (71%), the number of White participants among swimmers was four times higher than that of their Asian, Black, American Indian, and Latino counterparts. Furthermore, less than half of the respondents (44%) reported reading and following the posted beach signs with safety information, while around one-fourth (23%) reported swimming near lifeguards. We also found a strong association between the respondents’ knowledge about how to escape a rip current and reading beach ocean safety signs. The findings of this study contribute to previous research on rip currents and may assist in developing more effective ocean safety interventions for the diverse American public visiting various marine environments along the vast U.S. coastline.

Identification of Marine Landforms as a Form of Coastal Area Management in Pangandaran District

Changes in marine landforms in coastal areas are relatively rapid and need to be analyzed to determine environmental management policies. Complex marine landforms are found in the coastal areas of Pangandaran Regency and have strong pressure to fulfill community activities, not only for local communities but also for outside communities. Basically, community activities are adapted to regional environmental conditions. The aim is to optimize the potential of natural resources and minimize environmental degradation, but in reality, this has not been fully implemented. The method used in this research is a descriptive method using a field survey approach. Marine landforms resulting from the accretion process in the Pangandaran coastal area are spit landforms, aeolian-marine sedimentation in the form of coastal dunes, fluvio-marine sedimentation in the form of estuaries and alates, organic-marine landforms and white sand beaches associated with reefs. The landforms resulting from erosion are Cliffs, notches, wave-cut platforms, stacks, and stumps. The impact of landforms resulting from sedimentation in the Pangandaran coastal area is mainly spit landforms that cover river mouths and the occurrence of flooding, puddles, and even accumulation of organic waste, landforms resulting from erosion, the impact of which is the decline of the coastline accompanied by avalanches of material towards the sea, especially on beaches that have non-resistant rocks such as sedimentary rocks and alluvial deposits. Management of the Pangandaran coastal environmental area must be carried out in an integrated manner, land buritan (hinterland), which has steep slopes and resistant rock, is designated as limited production land, and the development of the spit at the river mouth is made into a jetty, and the beach has beach cups waves with rip currents and water bathymetry. -10 meters above sea level, a wave-protecting wall must be built, and the coastal border area must be used as vegetative-based conservation land.Keywords: Marine landforms, Coastal Management, Pangandaran

Do red and yellow flags indicate a danger zone?: Exploring Japanese university students’ beach safety behaviour and their perceptions of Australian beach safety signage

BackgroundCoastal drowning is a tragic regular occurrence in Australia, and in the decade 2012–2022, 455 overseas-born beachgoers drowned. Being one of the top five countries of international visitors who drown, Japanese tourists are an at-risk group. This study investigates Japanese university students’ knowledge of beach safety and their perceptions of Australian beach safety signage. MethodsThe present study conducted an online survey with 152 university students in Japan, comprising both closed and open questions. Although the survey was in Japanese, the signage terms used in the survey were in English as used in Australia. Descriptive analysis was conducted on the statistical data via SPSS and deductive thematic analysis was conducted on the open responses using Nvivo. Results90 % of them planned to visit beaches and 64 % would enter the water when or if visiting Australia. However, 60 % interpreted the safer supervised zone denoted by red and yellow flags as signifying a danger zone. Regardless of their English proficiency, almost none fully understood terms commonly used on safety and warning signs such as submerged objects, shore dump, shore break and rip currents, and 60 % of them didn’t know the Japanese term of rip currents, riganryuu. Visual icons were understood much better than these English terms. So what?This study explored a specific (i.e. Japanese) cultural perception and understanding of Australian beach signs beyond the scope of CALD communities. Future studies should continue exploring those of other cultures so Australian beach signs can be revised and improved based on scientific evidence.

Assessing NOAA Rip-Current Hazard Likelihood Predictions: Comparison with Lifeguard Observations and Parameterizations of Bathymetric and Transient Rip-Current Types

Abstract Rip currents, fast offshore-directed flows, are the leading cause of death and rescues on surf beaches worldwide. The National Oceanic and Atmospheric Administration (NOAA) seeks to minimize this threat by providing rip-current hazard likelihood forecasts based on environmental conditions from the Nearshore Wave Prediction System. Rip currents come in several types, including bathymetric rip currents that form when waves break on sandbars interspersed with channels and transient rip currents that form when there are breaking waves coming from multiple directions. The NOAA model was developed and tested in an area where bathymetric rip currents may be the most prevalent type of rip current. Therefore, model performance in regions where other types of rip currents (e.g., transient rip currents) may be more ubiquitous remains unknown. To investigate the efficacy of the NOAA model guidance in the context of different rip-current types, we compared modeled rip-current probabilities with physical-based parameterizations of bathymetric and transient rip-current speeds. We also compared these probabilities to lifeguard observations of bathymetric and transient rip currents from Salt Creek Beach, California, in summer and fall 2021. We found that the NOAA model skillfully predicts a wide range of hazardous parameterized bathymetric speeds but generally underpredicts hazardous transient rip-current speeds and the hazardous rip currents observed at Salt Creek Beach. Our results demonstrate how wave parameters, including directional spread, may serve as environmental indicators of rip-current hazard. By evaluating factors that influence the skill of modeled rip-current predictions, we strive toward improved rip-current hazard forecasting. Significance Statement The purpose of this study is to evaluate how well the NOAA rip-current hazard model predicts different rip-current types. Accurate forecasting of rip currents is important because rip currents are the leading cause of death and rescues at surf beaches worldwide. By comparing the performance of the NOAA model to parameterized rip-current speed and lifeguard observations of rip-current strength, we highlighted the model’s decreased ability to predict hazardous transient rip currents compared to hazardous bathymetric rip currents. Because bathymetric and transient rip currents are driven by different environmental conditions, an improved hazard model must be sensitive to these different conditions to predict a greater range of hazardous rip currents.

RipViz: Finding Rip Currents by Learning Pathline Behavior.

We present a hybrid machine learning and flow analysis feature detection method, RipViz, to extract rip currents from stationary videos. Rip currents are dangerous strong currents that can drag beachgoers out to sea. Most people are either unaware of them or do not know what they look like. In some instances, even trained personnel such as lifeguards have difficulty identifying them. RipViz produces a simple, easy to understand visualization of rip location overlaid on the source video. With RipViz, we first obtain an unsteady 2D vector field from the stationary video using optical flow. Movement at each pixel is analyzed over time. At each seed point, sequences of short pathlines, rather a single long pathline, are traced across the frames of the video to better capture the quasi-periodic flow behavior of wave activity. Because of the motion on the beach, the surf zone, and the surrounding areas, these pathlines may still appear very cluttered and incomprehensible. Furthermore, lay audiences are not familiar with pathlines and may not know how to interpret them. To address this, we treat rip currents as a flow anomaly in an otherwise normal flow. To learn about the normal flow behavior, we train an LSTM autoencoder with pathline sequences from normal ocean, foreground, and background movements. During test time, we use the trained LSTM autoencoder to detect anomalous pathlines (i.e., those in the rip zone). The origination points of such anomalous pathlines, over the course of the video, are then presented as points within the rip zone. RipViz is fully automated and does not require user input. Feedback from domain expert suggests that RipViz has the potential for wider use.

Vertical Distribution of Rip Currents Generated by Intersecting Waves in a Sandbar–Groin Systems

To analyze the impacts of groins, sandbars, and channels on the three-dimensional features of rip currents, we conducted experimental investigations on the vertical distribution of rip currents under intersecting waves along barred beaches with channels. This study employed ADV flow velocity measurements at two distinct locations: within channel and on a sandbar. The results indicate that in nodal sections within channel and on a sandbar, the rip head region manifests surface flow characteristics, characterized by high velocities near water surface. In a rip neck location, the vertical distribution of rip currents on a sandbar exhibits greater variability, whereas within channel, the distribution is more homogeneous. The vertical distribution of rip currents in nodal sections within channel aligns with the logarithmic distribution law. The vertical distributions of the alongshore velocity of rip currents display a consistent pattern of higher at the top and lower at the bottom. However, this pattern varies slightly depending on the wave period. The presence of groins influences the fluctuation characteristics of the alongshore velocity of rip currents by regulating the nearshore circulation system. This results in the alongshore velocity of rip currents in channel pointing towards the groin. In contrast, the alongshore velocity of rip currents on sandbar, situated farther away from groin, exerts a weaker effect on the alongshore velocity of a rip current.

Wave Breaking Eddies And Transient Rip Current Dynamics In Large-Scale Wave Basin Experiments

Rip currents transport contaminants, nutrients, larvae, and, unfortunately, occasionally even swimmers between the surf zone and inner shelf. Transient rip currents are ephemeral ejections associated with surfzone eddies that are ubiquitous even on alongshore-uniform beaches. During directionally spread wave conditions, depth-limited breaking along finite-length regions, known as short-crested breaking, leads to spatial variation in the breaking force and corresponding vertical vorticity input to the water column. An inverse energy cascade from the injected vorticity may result in larger scale horizontal surfzone eddies, consistent with two-dimensional turbulence. These large-scale eddies enhance dispersion within the surf zone and may mutually advect offshore as a transient rip current. While this hypothesis is widely discussed in the literature, we do not have strong observational evidence for the processes connecting the wave field to the formation of large-scale horizontal eddies. To overcome the challenges of isolating and measuring the processes leading to transient rip currents in the field, we examined these processes in large-scale laboratory experiments.

Seabird Spread in the Sarasota Bay

Seabirds are marvels that exist all along Florida coasts. However, very little has been done to study how they are spread in the Sarasota Bay. The interactions between different species and how they are spread in the Sarasota Bay is very important for this ever-changing ecosystem. Having biodiversity of all species in the Bay is very important so that this ecosystem can survive and thrive. This Bay is consistently impacted by red tide, hurricanes, rip current, and many other climate disasters. Seeing how seabirds are impacted by these occurrences is important for measuring the biodiversity of the Bay. The spread of 6 seabird species (cormorant, brown pelican, anhinga, ibis, spoonbill, and osprey) were measured for 14 different test sites in the Sarasota Bay, while also taking into account other species that were observed. One boat trip was taken each month in June, July, and August to observe the 6 seabird species, and the others sighted, at the 14 different test sites. At these 14 test sites over the three months, the most observed bird species were gulls. The least observed species were spoonbills. The most observed species for the targeted species were cormorants. However, no bird species was statistically significantly above or below one another. Therefore, the biodiversity in the Sarasota Bay seems to be at healthy levels, even with the climate disasters that have occurred. Support was provided by Dr. Toro-Farmer, including funding for the boat trips and access to GIS software. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Navigating the troubled waters of higher education – a phenomenological study on the needs and challenges of first‐year clinical associate students in South Africa

Background. Clinical associates (ClinAs) are educated in decentralised learning platforms where they gain skills and a concrete understanding of the fundamental challenges of healthcare in remote and poverty-stricken districts of South Africa. Due to the decentralised nature of the programme, these students seldom have access to ‘on-campus’ academic and psychosocial support. A peer mentorship programme has proved useful in this regard in other settings. Objective. To explore the unique academic and psychosocial challenges and needs of first-year clinical associate (ClinA) students and describe the views of the research participants on the perceived enablers and constraints of a ClinA peer mentorship programme. Methods. A phenomenological research design was used. The population included ClinA students and academic members of staff. Five appreciative inquiry interviews and two focus group discussions were conducted. Results. Four themes were identified: (i) flailing like a fish out of water (challenges experienced by ClinA students); (ii) floating devices (benefits of peer support programmes); (iii) the life saver (perceived enablers of peer support programmes); and (iv) rip currents (perceived constraints of peer support programmes). Conclusion. Unique challenges identified were: (i) the teaching and learning strategy implemented by the facilitator of the programme; (ii) the decentralised learning platforms; and (iii) the absence of institutional support at clinical learning centres. All participants agreed that peer mentor support is beneficial and essential for ClinA students, but that the peer mentor programme needs to be bespoke to address the limited access to academic and psychosocial on-campus support and the profile of the students, who are of rural origin and first-generation students.

Morpho-dynamic Induced Rip Currents in Klayar Beach, Pacitan, East Java, Indonesia

Klayar Beach (KB), Pacitan, East Java, Indonesia is a rugged coast with a narrow sand beach, a relatively small embayment with rocky headlands, and a very exotic view as a coastal tourism destination. Despite its attractiveness, KB poses a hazard due to rip currents. From 2009 to 2022, KB visited more than 3 million people, and more than 30 people were reported dead due to drowning in rip currents. This paper presents the result of fieldwork to investigate morpho-dynamic driven rip current hazard of the study area. This study carried out bathymetric and topographic mapping and sediment sampling. The last 10 years’ wave data was used for predicting hydrodynamic parameters. The study shows a good correlation between a variety of incoming significant wave heights and tide fluctuation vs. rip current velocity. The existence of headland plays a significant role in rip current formation in the study area. The headland influences either shadow or deflected rip currents formation for the incoming wave angle. The study also indicates that the type of rip current in the KB is structural boundary controlled, and the most important thing to be alerted for promoting beach safety in this area is that this rip current is predicted permanently to occur.

Perception of beach safety at a destination beach on the Great Lakes

AbstractSurf‐related drowning fatalities are a public health concern in the Great Lakes region of North America, and within Canada there are few beaches with lifeguards and no regional beach safety strategy. This short paper presents the results of a survey completed in the northern hemisphere summer of 2022 to determine the perceptions of beach users at Station Beach in Kincardine, Ontario, a popular tourist beach town on Lake Huron. Results suggest that beach safety knowledge and choice of location to occupy along the beach depend on experience with the beach, with frequent visitors tending to select quieter locations located further from a jetty that can result in a structural rip current. Infrequent visitors tended to be closer to the jetty and selected that location based on convenience (e.g., close to parking), suggesting the need for structural changes to guide behaviour towards safer areas of the beach. Results also highlight the challenges of developing an effective warning system to inform beach users of potentially dangerous surf and currents in the absence of an investment in lifeguards or a regional/provincial beach safety strategy.

The Impact of Rip Currents and Swell on Coastal Safety

Rip currents and swell pose significant threats to beach safety. Rip currents are powerful, channeled currents that can rapidly pull swimmers into deeper water, while swell refers to long, rolling waves generated by distant storms. This article examines the formation mechanisms, identification methods, and safety considerations associated with both phenomena. By understanding these risks, beachgoers and coastal management authorities can implement proactive measures to prevent accidents and ensure a safer coastal experience.

The Roles of Bathymetry and Waves in Rip‐Channel Dynamics

AbstractThe behavior and predictability of rip currents (strong, wave‐driven offshore‐directed surfzone currents) have been studied for decades. However, few studies have examined the effects of rip channel morphology on the rip generation or have compared morphodynamic models with observations. Here, simulations conducted with the numerical morphodynamic model MIKE21 reproduce observed trends in flows and bathymetric evolution for two channels dredged across a nearshore sandbar and terrace on an ocean beach near Duck, NC, USA. Channel dimensions, wave conditions, and flows differed between the two cases. In one case, a strong rip current was driven by moderate height, near‐normally incident waves over an approximately 1‐m deep channel with relatively little bathymetric evolution. In the other case, no rip was generated by the large, near‐normally incident waves over the shallower (∼0.5 m) channel, and the channel migrated in the direction of the mean flow and eventually filled in. The model simulated the flow directions, the generation (or not) of rip currents, and the morphological evolution of the channels reasonably well. Model simulations were then conducted for different combinations of the two channel geometries and two wave conditions to examine the relative importance of the waves and morphology to the rip current evolution. The different bathymetries were the dominant factor controlling the flow, whereas both the initial morphology and wave conditions were important for channel evolution. In addition, channel dimensions affected the spatial distribution of rip current forcings and the relative importance of terms.

Constrained Vapor Bubble Experiment (CVB) in the Light Microscopy Module (LMM)

Abstract This short article describes the major findings from the CVB experiment performed in the LMM on the International Space Station from 2010–2012. CVB was the first experiment to run in the new facility and focused on understanding the heat transfer and fluid mechanics occurring inside a wickless miniature heat pipe. The LMM was used to map the location of the vapor-liquid interface inside the device and to measure the film thickness profile on the walls of the device. Several interesting and unexpected phenomena were observed in microgravity including flooding of the heater end with liquid as the heat input increased, explosive nucleation of vapor bubbles at the heater end in the shortest version of the heat pipe tested, condensation on highly superheated surfaces, and the spontaneous formation of rip currents as the device tried to enhance the contact line area available for evaporation of the liquid.

Vulnerability of the rip current phenomenon in marine environments using machine learning models

Hidden and perilous rip currents are one of the primary factors leading to drownings of beach swimmers. By identifying the coastal areas with the highest likelihood of generating rip currents, it becomes possible to prevent fatalities and mitigate economic losses associated with these hazardous currents. Rip currents are characterized as streams of water moving towards the open sea, forming within the area where waves break, due to variations in wave-induced radiation stresses and pressure along the coastline. This study utilized nine different Machine Learning (ML) models, including M5 Model Tree (MT), Multivariate Adaptive Regression Spline (MARS), Gene Expression Programming (GEP), Evolutionary Polynomial Regression (EPR), Random Forest (RF), Support Vector Machine (SVM), Extreme Gradient Boosting (XGBoost), Adaptive Boosting (AdaBoost), and Stacked ML models, to estimate the Relative Tide Range (RTR) values for 50 southern beaches in China. Through this approach, we gathered a reliable dataset from prior research conducted on the southern coast of China. In this study, two parameters, namely dimensionless fall velocity parameter (Ω) and tide range (TR) are used to predict the vulnerability of rip current event. The results of the AI models were assessed by various statistical analyses (Correlation of Coefficient [R], Root Mean Square Error [RMSE], violin diagram, heatmap, and taylor diagram) for training and testing stages. Accordingly, the MARS model exhibited superior performance compared to other AI models in accurately predicting the RTR value. The outcomes substantiated the significant effectiveness and capability in estimating the RTR with high accuracy. Southern China coasts have relative high risk level of rip current, necessitating the attention and strategic management of this dangerous current by the beach managers.