Destructive Swells to Impact Much of the Atlantic Basin This Week – Including the Caribbean

27 10 2019

Dale C. S. Destin|

A major swell event is forecast to impact much of the Atlantic Basin this week, including Antigua and Barbuda and the rest of the Caribbean, washed by the Atlantic. The swells are expected to cause high surfs and powerful rip currents, which will be a severe threat to life and property, mainly in the surf zone. There is also the increased likelihood of damage due to flooding of some low-lying coastal areas.

Swells Forecast For Friday Nov 1, 2019

Swells reaching the region are expected to rise to over 3 metres (over 10 ft) and locally or occasionally exceeding 3.5 metres (12 ft), coming out of the northeast. These swells will result in dangerous, life-threatening surfs for beachgoers and other users of coastal areas; hence, advisories and or warnings will be required. Some meteorological services have already issued marine alerts on the event – see information coming out of your national meteorological service for the specifics on this event.

Swells heading our way – Antigua and the Caribbean, have spiked to near 14 feet (4 metres). At periods of 10-15 seconds, it takes 8 to 12 hours for swells to reach us from this buoy/weather station. Please note that we may not see 14 ft swells in the area; however, they are expected to, at least, peak over 10 feet, with higher surfs – causing very hazardous, life-threatening conditions at near-shore/coastals areas. 

The swell event started four days ago by hurricane-force winds associated with an enormaous low-pressure area, which contained Hurricane Pablo and a very powerful extra-tropical cyclone. Since then, Pablo has dissipated and the extra-tropical cyclone ahs transitioned to Subtropical Storm Rebekah. Of course, the extreme weather directly associated with the low never had a chance of reaching the Caribbean and Rebekah likewise has no chance of directly impacting the region.

The Enormous Low-Pressure Area Generating the Swells

The swells in and of themselves are not the real concern. The greater concern is the large breaking swells or high surfs that these swells will caused when they reach the shorelines of the region. Such long period swells can result in surfs as high as twice their heights i.e. in excess of 6 metres ( in excess of 20 ft), in some areas.

Puerto Rico’s Met Service is Forecasting Surfs to Exceed 15 Feet (4.5 metres)
High Surf - Fort James, Antigua
Past High Surf – Fort James, Antigua

The eventual heights of the surfs are largely dependent on the bathymetry (shape and depth) of the near shore coastal areas they interact with. Generally, the shallower the near shore areas, the higher the surfs. The greatest impact will be on the north, northeast and east-facing beaches and coastlines.

The event has started across the northeast Caribbean and will reach the southern Caribbean and South America, including the Guyanas by tomorrow – Monday. A second pulse of dangerous swells will reach the Caribbean by late Thursday. These swells are also forecast to reach the east coast of the United States, Canada and as far away as Greenland, Iceland, the United Kingdom, Europe and Africa.

These high surfs will have the potential impact of injuries or loss of life, beach closures and financial losses. Impacts could also include:

  • disruption to potable water from desalination;
  • salt water intrusion;
  • flooding of low-lying coastal roads;
  • beach erosion;
  • disruptions to near shore marine recreation and businesses;
  • damage to coral reefs and
  • disruptions of marine transportation.

These swells and surfs could result in strong rip currents that can carry even the strongest swimmers out to sea. Rip currents are powerful channels of water flowing quickly away from 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 concern for those who visit non-beach coastal areas. High surfs can knock spectators off exposed rocks and jetties. Those who rock fish need to pay attention and not expose themselves to this hazard. Breaking waves may occasionally impact harbours making navigating the harbour channel dangerous.

With this event happening during or near a new moon, coastal flooding and erosion are more likely than usual. Coastal flooding from the sea is largely depended on high tides, onshore wind and swell actions.

The potential impacts listed above are just that – potential/possible impacts. I am not saying that they will all definitely happen, but conditions could result in such and past similar swell events have caused such.

If an high advisory is issued for an area – be extremely cautious; bathe only where lifeguards are present. If a high surf warning is issued – do not enter the water. Relatively safe conditions are likely on the opposite, or in this case, the southern sides of the islands.

Swells and associated surfs will peak across the Caribbean tonight and or Monday and again Thursday and or Friday. The highest swells across the region are likely across the northeast Caribbean – Antigua and Barbuda and the rest of the Leeward Islands.

I will keep you updated on this event via TwitterFacebook and Instagram. Please share this blog, if you found it useful and follow me for more on all things weather and climate.

Editor’s note: This post was originally published Oct 27, 2019 and updated on Oct 31, 2019 to reflect changing conditions.

October 8, 1974 Earthquake and Weather Remembered

8 10 2019

Dale C. S. Destin |

October 8, 1974, a clear, cool and calm Tuesday morning, Antiguans and Barbudans had a wakeup alarm of seismic proportion. At 5:50 am 45 years ago today, the region had a powerful 7.5 magnitude earthquake that shattered the day.


The October 8, 1974 quake is said to have produced the strongest shaking in several Leeward Islands since the great earthquake of February 8, 1843. It is actually the strongest ever recorded in the Eastern Caribbean, according to UWI, Mona. The 1974 quake was also three times stronger than the Haiti 7.0 magnitude quake of 2010.

A few people are said to have received minor injuries, but no fatality was reported, according to paper – Reconnaissance report of the Antigua West Indies, earthquake of October 8, 1974. The paper also indicated that “damage was confined mainly to larger and older buildings, to a petroleum refinery [West Indies Oil Refinery], and to the deep-water harbour”.

I was 5 years old back then, to young to remember much. I don’t have any memory of feeling the actual quake, but I do recall quite vividly that when the wooden grocery shop (Bascus Shop – Bennett Street, Villa) next door opened, all the goods were on the floor.

And what was the weather like? A look at the weather records of October 8, 1974 as taken at the V. C. Bird International Airport, Antigua; it was a calm night with mostly clear skies. The mean temperature was around 24 C or 75 F with a relatively cold minimum temperature of 22 C or 72 F.

At the actual time of the quake (5:50 am local time, 1050 UTC), the wind was calm with fair skies (one okta of low-level clouds and four oktas of high-level (cirrus) clouds).  The temperature was a cool 22 C or 72 F and the relative humidity was 96%.

The weather observer also noted that there was a thunderstorm (Cumulonimbus) cloud to the northeast of the Airport but no thunder was observed. Up to October 8, 1974, the rainfall for the month was 89.9 mm (3.54 inches), which is quite a lot for only 7 days. 

Summarizing the night leading up to the most destructive quake on record for the area: it was mostly clear, calm, fairly cool and dry in terms of the absence of rainfall; however, much dew would have formed as the wind was calm all night and the relative humidity in the 90’s.

Questions: What would happen if a similar quake occurred today? Are we better prepared today than we were in 1974? The UWI Seismic Unit has been cautioning that they have seen activities over the past few years similar to the lead up to the 1974 quake; are we heeding this caution?

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