As mentioned in the last number of posts, we are still in St. Lucia as the pandemic has locked down all East Caribbean Islands (ECI’s) for inter-island and international travel. They are starting to “open up” as I write this as the spread of the virus has been blunted by the lock down and controls of the islands. Grenada just opened its border to cruisers from other islands seeking safe haven for the hurricane season. We anticipate that Trinidad will do the same, hopefully in June.
The official hurricane season is June 1 to November 30. This is declared by the National Oceanic and Atmospheric Administration (NOAA) and covers the time period for the vast majority of hurricanes for the year. NOAA also gives these storms names so that the public can follow them easily. Tropical Depressions and Tropical Storms, which proceed or follow the evolution of Hurricanes carry the same name. In other words, systems that are tropical in nature which could develop into hurricanes, whether they do or not, are named.
Needless to say, boats and ships try to avoid these destructive “named” storms. Insurance companies don’t like them either. Most insurance coverage explicitly spells out that there is no or limited coverage during the “season” in the specific hurricane “box”. No wonder then, that boat owners move away from where hurricanes and named storms tend to gather in “the box”. So where oh where will my hurricanes be?
That brings up the crystal ball forecasts that NOAA and many others issue regarding the Hurricane Season. “It’s going to be an above/below/average season, with such and such storms”. A full-throated justification with all sorts of detailed theories, reasons, analysis, percentages etc. of why this will be so. Interesting but what use is it? How should I react knowing that we will get 16 storms (maybe) rather than an average of 14? All it takes is one to ruin your day.
Hurricanes and storms spawn and exist in an area from Africa to Mexico to New England, in other words, a very big area! Compared to that area, the area of an individual storm is really small. Some are larger than others and can affect large areas. In any case, you cannot discount the destruction if you are ever near one. Fortunately forecasting the track, intensity and time frames for individual storms get better each year. And that is much more important than what the “season” will bring. There is no way anyone can forecast months in advance when, where, how big or much of anything about these storms. At best, maybe two weeks before initial development, something might be noticed. And even then, where its heading or how strong it will be is not certain at all. But we can look at history.
NOAA has great public records of all weather forecasts (to verify how accurate they were) but what I was interested in was the actual track of the hurricanes and named storms in the ECI’s (Virgins to Trinidad) over the last 30 years. NOAA publishes a track map for each year which I studied and then compiled the table below (you could also analysis how accurate their forecasts were).
The data needs some explanations. The table lists only NOAA’s named Tropical Depressions, Tropical Storms, Hurricanes and Major Hurricanes. Hurricanes go through stages of strength and organization and so these are the classifications of the “named” storms. There are also tropical waves, subtropical and ex-tropical systems, heavy squalls etc. which may offer sever weather but were not included. I wanted to concentrate on the named storms.
Each storm listed crossed over or between the island chain (Leeward and Windward plus Trinidad – ECI’s) on the date indicated. Don’t assume that winds and destruction only occurred on the islands mentioned. It is only the center (eye) that was noted, neighboring islands would also have experienced effects of the storm. This is especially true of the small islands like Saba, St Kitts etc. Storms evolve over time and therefore become stronger or weaker as they churn their way from the east to the west. You may note that a storm is notated as a Tropical Storm, but you may remember it as a Major Hurricane. That is because it was only a Tropical Storm at that point. Storms that did not pass thru or were not close were not listed. Storms that only hit Puerto Rico, DR and north were not listed. I only looked at the last 30 years. Data goes back much further if a true climatology study was to be done. In any case, this is just a look at the last 30 years, I don’t intend it to be anything more than that.
What did I find? The number of named storms in the Atlantic, 1998 to 2019, totaled 431. Of that, only 59 crossed over or through the East Caribbean Islands (ECI’s). That is less than 14% of the totaled named storms. Of these ECI’s storms, 6 were tropical depressions, 34 tropical storms, 10 hurricanes and 9 major hurricanes. Meaning only 19, 4.4%, of all Atlantic named storms during that period were hurricanes that hit one or more ECI’s.
The official season is June 1 to November 30. However, Atlantic named storms did occur from April to December. One storm, hurricane Alex in 2016 tracked from January 12 to 15 in the central Atlantic. In the ECI’s, all named storms only occurred during the official season. In 4 of the years there were no storms at all in the ECI’s: 1991, 1992, 1997, 2003.
Of the 59 ECI’s storms, the majority, 76%, were Tropical Storms. Hurricanes accounted for 42% and Tropical depressions were 11%.
Where were they? This became interesting. It is popularly believed that Trinidad has no storms and as you go north from there the numbers, and therefore the chances of getting one, increase. Looking at the numbers however (last 30 years only) shows that Trinidad had 5 storms: 2 Depressions, 3 Tropical storms (no hurricanes). Grenada had 11 storms: 1 Depression, 9 Tropical storms, 1 Major hurricane. All the way up north, the Virgin Islands had 10 storms and 7 were hurricanes. Between Grenada and the Virgin Islands the range varied from 5 to 8 storms each, almost even distribution. The take-away is that Trinidad did indeed have the lowest number of storms and that Grenada is not as immune to storms as believed. In fact, Grenada is only second to the Virgins in number of storms. The most other islands had considerably fewer but not as few as Trinidad. It is noted, however, that the strength of the storms increased as you go north from Trinidad to the Virgins. The Virgins had 4 hurricanes and 3 major hurricanes.
Other interesting points. All storms formed east of the ECI’s and traveled westward except 3: Sebastine 1995, Lenny 1999, and Omar 2008. All 3 had a track with an easterly component. Both Lenny and Omar were major Hurricanes when they were in the ECI’s. Lenny was also interesting because just a month before, Hurricane Jose tracked the same path but in the reverse direction. Iris in 1995 has the record for hitting all islands between Martinique and St. Martin when it tracked up the chain.
Finally, what was the trend overall of storms during the last 30 years? The below graph indicates that named storms in all the Atlantic trended up. Storms in the ECI’s may also show that trend but not as pronounced. Storms per year ranged from 7 to 28. Twenty-eight in 2005 was off the chart! The average number for all storms was 14.3/year (13.8 if you delete 2005). ECI’s average was 2.
A popular often asked question are storms getting bigger or stronger. That is beyond the scope of this review although you certainly can get data from NOAA to get some idea. Actually, that question is much more difficult to answer and there is no definitive answer…yet.
So, where oh where will this year’s hurricanes be? TS Arthur already formed, nowhere near the ECI’s. All I will say is that, yes there will be hurricanes and storms this season. And Lord knows where they will be.