By Christopher Alexis, Researcher, Oceanography & Coastal Processes Department
Trinidad and Tobago’s beaches have been re-opened after a lengthy closure because of the COVID -19 pandemic. Our citizens may once again enjoy the coastal waters that surround our twin island republic. Notwithstanding our love for the sea, the Institute of Marine Affairs strongly advises that the public exercise caution on the nation’s beaches, particularly over this Easter weekend, as our heightened excitement may reduce our awareness of the coastal environment.
During the year from an oceanographic perspective, there are the summer (May to October) and the winter (November to April) periods. The summer months have characteristically smaller waves (lower wave energy) and generally create safer bathing conditions as the coastal waters are calmer, although there is the possibility of the infrequent storm. Throughout the winter months the waves are larger (higher wave energy) and bathers should pay attention to sea conditions as the likelihood of strong nearshore currents (e.g. rip currents) is increased.
Rip currents usually occur in close proximity to breaking waves and are common within pocket beaches with moderate to high wave energy. In Trinidad, these beaches may be found on the north coast (e.g. Maracas and Las Cuevas) and along the unsheltered east coast (e.g. Mayaro). In Tobago, rip currents may occur on most beaches that are not protected by coral reefs. These currents are dangerous and contribute to drowning occurrences annually particularly during celebratory times of the year.
Rip currents are powerful flows of water moving seaward that can effortlessly drag unsuspecting bathers quickly out to sea. They characteristically extend from the shoreline, across the surf zone (the area of breaking waves bounded by the point of first breakers, then landward to the maximum uprush of waves on the beach), and beyond the line of breaking waves.
The term rip currents are sometimes interchangeably used to refer to rip tides, undertows or undercurrents but this is incorrect:
Rip tides – includes both ebb and flood tidal currents that are caused by egress and ingress of the tide through inlets and the mouths of estuaries, embayment’s and harbours. These currents may cause drowning deaths, but these tidal currents or jets are a separate and distinct phenomenon from rip currents.
Undertow – a process related to waves breaking on the beach where an imbalance of pressure allows water to flow back out to sea under the waves. It can cause a tug at your legs.