Hazardous Seas Alert In Effect From 5 AM Saturday

The Hazardous Seas Alert

As we’ve mentioned earlier, a long-period swell event is forecast to affect Trinidad and Tobago beginning on early Saturday and into next week.

The Trinidad and Tobago Meteorological Service has now issued a Hazardous Seas Alert (Yellow Level) for our coastal waters beginning at 5:00 AM Saturday 4th April 2020 through 9:00 PM Sunday 5th April 2020.

While the start period of this alert lines up well with global modeling for the arrival of the swells, and peak swells are forecast to occur during the alert period, long period swells are forecast to continue into mid-next week.

Since winds are forecast to remain moderate, seas will generally remain the same, with conditions in open waters below 2.0 meters.

Trinidad and Tobago is NOT under any tropical storm threat, watch or warning.

Based on the latest model guidance and analysis, swell periods may range from 10-17 seconds, capable of producing large, dangerous breaking waves in bays, beaches, and other nearshore areas. This means that wave heights in bays and beaches may reach up to 2.5 meters, depending on the bathymetry of the area.

Battering waves in nearshore areas are forecast between Saturday and Wednesday, particularly during high tide periods. Coastal flooding is also likely in low-lying coastal areas. Beach and coastal erosion are likely. Overall, there is a high risk of rip currents and large waves at beaches so disruptions to beachgoers and marine interests are expected. Note that although the alert from the TTMS is not in effect for Eastern and Southeastern coastlines of T&T, these areas may also experience battering waves.

King tides are forecast, so we may see exacerbated effects during those high tide periods.

Information from the Trinidad and Tobago Meteorological Service concerning the Hazardous Seas Alert in effect from 5 AM Saturday through 9 PM Sunday.

“A combination of northerly long period swells and spring tides will likely cause agitation of nearshore sea conditions, especially at high tide, along the northern coastlines of Trinidad and Tobago, and to a lesser extent, the western coastline of Trinidad.” according to the Trinidad and Tobago Meteorological Service. This “alert” status takes into account the possibility of the event occurring. This event is likely.

The color of the alert indicates the severity of the event and the probability of the event occurring. Currently, the alert level is at Yellow. This means that the hazard is likely and you need to be aware of the impacts of hazardous seas in your area. Moderate impacts are expected, so there is the chance of possible injuries and persons would need to take action to ensure safety. There may be minor damage to property.

Image Credit: Trinidad and Tobago Meteorological Service

7-Day Sea Forecast

Hazardous seas will be attributed to two reasons, King Tides and long-period swells.


These long-period swells (with 10-17 second periods) are forecast to begin affecting T&T’s coastal waters, originating from the North. These swells will mainly affect Northern, Eastern, and Western coastal waters of both islands between Saturday through mid-next week.

Seas Forecast

Sea state forecast through the next 7 days, as moderate seas with long period swells (and King Tides) occur across Trinidad and Tobago.

The general sea state through the next 7 days is as follows:

Saturday 4th April to Sunday 5th April: Moderate. Low-level winds between 10-15 knots, predominantly from the southeast, are forecast across the region. Generally, in open waters, waves up to 2.0 meters with waves up to 1.5 meters in sheltered areas due to long-period swells. Spring tides are ongoing so minor coastal flooding possible in low-lying coastal areas.

Monday 6th April to Wednesday 8th April 2020: Moderate. Low-level winds between 15-20 knots, predominantly from the east to northeast, are forecast across the region. Generally, in open waters, waves between 1.5 meters and 2.0 meters and between 1.5 meters to 1.0 meter in sheltered areas. A combination of King tides (that begin on Tuesday) and long-period swells, large battering waves are possible affecting coastlines of both islands. Swells may bring waves up to 2.5 meters in nearshore areas!

Thursday 9th April through Friday 10th April 2020: Moderate. Low-level winds between 15-20 knots, predominantly from the east to northeast, are forecast across the region. Generally, in open waters, waves between 1.5 meters and 2.0 meters and near calm in sheltered areas. King tides will continue, with possible coastal flooding in low-lying areas during high tide periods.

Approximate high tides for Port of Spain, Trinidad, and Scarborough, Tobago are seen below. Low-lying coastal areas may experience coastal flooding, particularly 30 minutes prior and 30 minutes after when peak high tides occur though this week.

High Tide Forecast for Trinidad over the next 7 days as King tides, long period swells and moderate seas forecast.
High Tide Forecast for Tobago over the next 7 days as King tides, long period swells and moderate seas forecast.

Impacts on T&T’s Shorelines (Mainly Saturday through Monday)

Impacts possible from rough seas include the following:

  • Loss of life;
  • Injuries;
  • Sea search and rescue disruptions;
  • Disruptions to sea transportation;
  • Scarcity of seafood;
  • Damage or loss of boats and fishing equipment;
  • Disruptions to marine recreation and businesses
  • Economic losses.

Other impacts from the high winds, apart from hazardous seas, include:

  • Injuries;
  • Coastal erosion;
  • Localized disruptions of businesses;
  • Disruption to outdoor and sporting activities;
  • Disruption of transportation (air and especially sea) and

There is also the potential for loss of life. There is a high risk of rip currents, strong currents that can carry even the strongest swimmers out to sea.

Rip currents are powerful channels of water flowing quickly away from the shore, which occur most often at low spots or breaks in the sandbar and near structures such as groins, jetties, and piers. If caught in a rip current, relax and float. Don’t swim against the current. If able, swim in a direction following the shoreline. If unable to escape, face the shore and call or wave for help.

There is also the potential for injuries to beachgoers; beach closures; localized disruptions to marine recreation and businesses and financial losses.

High tides combined with onshore wind and swell actions could result in localized coastal flooding and beach erosion.

High surfs can knock spectators off exposed rocks and jetties. Breaking waves may occasionally impact harbors making navigating the harbor channel dangerous.

Saltwater will likely splash onto low-lying coastal roads such as the South Trunk Road at Mosquito Creek, the Guayaguayare Mayaro Road at the Guayaguayare Sea Wall, and the Manzanilla-Mayaro Road. Bays and beaches may become inundated.

Coral reefs may experience increased stress and damages, in addition to localized beach erosion, particularly in areas where battering waves focus.

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