- The South African Weather Service has launched a first-of-its-kind rip current forecast model to enhance safety at six Cape Peninsula beaches.
- The system uses advanced data to predict and warn about hazardous rip currents, helping beachgoers and lifeguards reduce drowning risks.
- The forecast will roll out this festive season, with plans to expand to other regions in South Africa.
The South African Weather Service (SAWS) recently unveiled a breakthrough innovation in rip current forecasting aimed at helping Cape Town beachgoers and lifeguards to anticipate hazardous seashore conditions.
This initiative will help curb drowning incidents at six beaches along the Cape Peninsula coastline – Blouberg Beach, Milnerton Beach, Fish Hoek Beach, Monwabisi Beach, Strand Beach and Kogel Bay Beach.
Rip currents are strong, narrow channels of fast-moving water that extend seaward from close to the shoreline into and beyond the surf zone. They can occur at any beach with breaking waves and can move at speeds of up to 2,4 meters per second, making them difficult for even strong swimmers to overcome.
Such currents are responsible for over 100 deaths annually worldwide and are linked to more than 10 000 drownings globally. The number of fatalities can vary by location and year. In South Africa, rip currents remain one of the leading causes of coastal fatalities, with the National Sea Rescue Institute (NSRI) reporting a significant contribution to drownings at South African beaches.
A first of its kind
During the 2017-’18 and 2018-’19 beachgoing seasons, the City of Cape Town reported 30 fatal drownings, many of which were linked to rip currents. However, accurate and consistent reporting on rip current-related fatalities is often limited, suggesting that the actual number of deaths may be higher.
Speaking at the Rip Current Hazard Forecast model launch in Milnerton, SAWS’ Senior Manager: Marine, Lebogang Makgati said the model was the first of its kind as South Africa has not had scientific means of predicting the occurrence of rip currents before.
Makgati explained that the forecast would be beneficial to beaches along the Cape Peninsula coastline, adding that the locations in question were selected based on the high number of rip current incidents recorded during the model development phase.
She further clarified that rip currents could still occur at other beaches in and around the Cape Peninsula that were not part of the primary focus area of the development of the newly-developed model.
“This forecast will benefit the public by providing timely and accurate information on rip current hazards, allowing beachgoers to make informed decisions about when and where to swim. By improving awareness, the forecast helps reduce the risk of accidents and fatalities, enhancing safety,” Makgati said.
“It also empowers lifeguards and emergency responders to better prepare and respond to potential incidents, ultimately contributing to a safer coastal experience for everyone.”
How it works
The model uses modelled wind, wave, and tidal data from the SAWS Marine Model as daily input for metocean forecast data. Using these inputs, the system assesses conditions to evaluate the potential for rip current formation.
It assigns a “rip risk” level to each of the six monitored beaches along the Cape Peninsula. This risk level indicates the likelihood of rip currents forming, based on data such as wave height, wave direction, tidal stages, and wind characteristics. Higher risk levels suggest conditions that strongly favour rip current development.
The model then produces daily forecast outputs, which include specific times and locations with the highest rip current risk and practical, colour-coded risk levels that simplify risk communication, making the information actionable for lifeguards, emergency responders and beach managers.
The SAWS will commence the implementation of the model in the 2024 festive holiday season, during which period the City of Cape Town is known to receive an influx of holidaymakers, some of whom go on to visit some of the city’s beaches.
The forecast information will be accessible through the SAWS marine web portal. Work is in progress to extend it to beaches in the Eastern Cape and KwaZulu-Natal.
“The development of the model was funded by the Weather and Climate Science Partners of South Africa through the United Kingdom (UK) Met Office, which played the role of delivery partner on behalf of the UK government’s Newton Fund. The SAWS worked with a host of domestic and international partners to develop the model. These include LifeSaving South Africa, City of Cape Town, National Sea Rescue Institute, Stellenbosch University, South African Environmental Observation Network, Coastal Marine Applied Research and University of Plymouth.
