POSTSCRIPT

A Great One Rarely, if Ever, Suf­fers a Di­rect Hit

Passage Maker - - @ Rest -

Pe­ter Swan­son chan­nels his in­ner John McPhee as he ex­plores the ge­o­log­i­cal virtues of the per­fect hur­ri­cane hole.

Amore se­cure har­bor than any in Flor­ida, which suf­fered 2,000 sunk and bro­ken boats dur­ing Hur­ri­cane Irma. Bet­ter, too, than any­where in the bat­tered Vir­gin Is­lands. Bet­ter than any­where in the Caribbean north of Trinidad. Heck, his­tor­i­cal storm data shows this place is safer from hur­ri­canes than Rhode Is­land.

The place of praise is a har­bor on the North Coast of the Do­mini­can Re­pub­lic. Lu­peron is the down-is­land hur­ri­cane hole of hur­ri­cane holes. Off and on, I spent a cou­ple years there at an­chor, some while work­ing on tourist cata­ma­rans at nearby re­sorts.

Peo­ple need to be care­ful when they talk about hur­ri­cane holes be­cause some­body who doesn’t know any bet­ter just might be­lieve them. I took is­sue re­cently with a fel­low who in­sisted Great Har­bour in the Ba­hamas was a “great hur­ri­cane hole.” It was a hur­ri­cane hole, I agreed, but not a great one be­cause there can be no great hur­ri­cane holes in the Ba­hamas. That low-ly­ing ar­chi­pel­ago might as well be cat­nip to hur­ri­canes.

Ge­ol­ogy as well as ge­og­ra­phy has made Lu­peron a great hur­ri­cane hole for sev­eral rea­sons—some ob­vi­ous and some not. A nar­row en­trance opens into two basins, both of which are sur­rounded by hills and have deep sticky muck for hold­ing. But the har­bor has a cli­ma­to­log­i­cal ad­van­tage as well. The best shel­ter in the world isn’t much good if the lo­ca­tion it­self is a hur­ri­cane mag­net. The op­po­site is demon­stra­bly true in the case of Lu­peron, which has not had a di­rect hit since hur­ri­cane track­ing be­gan in 1851.

Irma came close in Septem­ber, pass­ing 50 miles north of Lu­peron as a Cat­e­gory 5. Nei­ther Irma nor Maria did much harm to Lu­peron, which as usual pro­vided refuge for dozens of for­eign cruis­ing ves­sels as well as na­tive com­mer­cial craft from across the Do­mini­can Re­pub­lic’s North Coast and the Turks and Caicos. The late­com­ers ran lines from their bows into the dense man­groves that sur­round the har­bor and fin­ished the job with stern an­chors. Man­groves are an­other fea­ture that make a hur­ri­cane hole great by pro­vid­ing some­thing flex­i­ble and for­giv­ing should a ves­sel be blown ashore. They are surely bet­ter than con­crete bulk­heads and pil­ings.

THE WEATHER

My main man for weather, es­pe­cially through­out the Ba­hamas and Caribbean, is weather router Chris Parker. Parker likes Lu­peron as a hur­ri­cane hole be­cause of two over-arch­ing fac­tors: Hur­ri­canes at this lat­i­tude tend to move from east to west, and Lu­peron Har­bor has its back to a moun­tain range called the Cordillera Septen­tri­onal.

The il­lus­tra­tion at top shows Lu­peron Har­bor. The other shows the Vir­gin Is­lands to­tally ob­scured by mul­ti­ple hur­ri­cane tracks since the mid-19th cen­tury. Lu­peron has had a few di­rect hits by trop­i­cal storms (green lines) but none by hur­ri­canes. Note that two of these storms be­gan as hur­ri­canes but lost their strength cross­ing the moun­tains of the Do­mini­can Re­pub­lic.

Parker ex­plains the sci­ence be­hind his think­ing:

Pru­dent mariners know a hur­ri­cane’s right-front quad­rant (rel­a­tive to its for­ward mo­tion) is typ­i­cally the most dan­ger­ous part. In the right-front quad­rant, not only do winds blow to­ward the path of the hur­ri­cane, but strength of wind in­creases by the for­ward speed of the hur­ri­cane. We typ­i­cally find about 90 per­cent of tor­na­does and wa­ter­spouts and most de­struc­tive mi­crobursts in this quad­rant.

Con­versely, the left quad­rants of a hur­ri­cane forms its “nav­i­ga­ble semi­cir­cle.” In these left quad­rants, where wind blows away from the path of the hur­ri­cane, we sub­tract two times its for­ward speed from the “max sus­tained wind” (usu­ally found in the right-front quad­rant), so we typ­i­cally see fewer se­vere weather events here.

To il­lus­trate the dif­fer­ence in wind speed due sim­ply to storm mo­tion, let’s ex­am­ine a sta­tion­ary Cat­e­gory 2 hur­ri­cane with 90knot sus­tained winds. Put the hur­ri­cane in mo­tion at 10 knots of for­ward speed and the mov­ing hur­ri­cane will sup­port 100-knot winds (Cat­e­gory 3) in its right-front quad­rant, but only 80-knot (Cat­e­gory 1) winds in its left-front quad­rant.

In ad­di­tion, al­though hur­ri­cane struc­ture varies, with most west-mov­ing hur­ri­canes along the lat­i­tude of the North­ern Caribbean, the bulk of in­bound trop­i­cal mois­ture feeds from the south into the right-front quad­rant while air feed­ing into the left­front quad­rant is pulled from the north (drier mid-lat­i­tudes).

No lo­ca­tion in the western North At­lantic is com­pletely safe from hur­ri­canes, but if we were look­ing for a rel­a­tively safe spot, it would lie on the north coast of a large moun­tain­ous land­mass. Al­most all hur­ri­canes move in a gen­eral west­erly di­rec­tion dur­ing most of their time in the trop­ics. Later they turn north, then north­east or east-north­east. There are ex­cep­tions, but this is the usual pat­tern.

If a west-mov­ing hur­ri­cane passes along—or just north—of the north coast of our large moun­tain­ous land­mass, then har­bors along the north coast will ex­pe­ri­ence the weaker south side (left­front quad­rant) of the hur­ri­cane.

If a west-mov­ing hur­ri­cane passes over our large moun­tain­ous land­mass, dry air and tall moun­tains dis­rupt the hur­ri­cane’s struc­ture, caus­ing a rapid weak­en­ing of the en­tire sys­tem.

If a west-mov­ing hur­ri­cane passes south of our large moun­tain­ous land­mass, then it is so far from the north coast that con­di­tions on the north coast are mild.

Where can we find a pro­tected har­bor along the north coast of a large moun­tain­ous land­mass? Lu­peron is one ex­cel­lent ex­am­ple:

In order for a west-mov­ing or north­west-mov­ing hur­ri­cane to af­fect Lu­peron, it would have to pass over 100 to 200 miles of the moun­tain­ous Do­mini­can Re­pub­lic, in­clud­ing sev­eral peaks over 10,000 feet lo­cated south of Lu­peron. This would se­verely weaken the hur­ri­cane, min­i­miz­ing dam­age.

The north coast of Cuba en­joys a sim­i­lar topo­graph­i­cal ad­van­tage, and there is a har­bor very sim­i­lar to Lu­peron called Puerto Vita, which ben­e­fits from the same over­all track­ing pat­terns and to­pog­ra­phy.

I will con­fess that Lu­peron was more in­ter­est­ing 20 years ago than it is to­day. The cruis­ing com­mu­nity then in­cluded many real-deal mariners from all over the world, and there would be as many as 120 boats in the an­chor­age dur­ing hur­ri­cane sea­son. Most were oc­cu­pied.

In the in­ter­ven­ing years, as word spread of Lu­peron’s shel­ter and rel­a­tively low crime rate ( just a few bur­glar­ies in a bad year), more Amer­i­cans have cho­sen the har­bor to store their boats unat­tended. This is al­most never a good thing for the neigh­bor­hood. That’s why well-man­aged an­chor­ages such as Boot Key Har­bor in Marathon, Flor­ida, for­bid long-term unat­tended ves­sels. This type of har­bor man­age­ment, how­ever, is not yet prac­ticed by Do­mini­can au­thor­i­ties.

The good news I took away from my re­cent visit to Lu­peron is that the rus­tic Puerto Blanco Ma­rina, the so­cial cen­ter for the cruis­ing crowd, has ren­o­vated its restau­rant and docks, thanks to new man­age­ment.

The Do­mini­can Re­pub­lic is one of the most beau­ti­ful coun­tries in the world, but un­like Cuba, it is blessed with few nat­u­ral har­bors. Con­se­quently, it is best ex­plored by land. So any­one seek­ing shel­ter from storms and want­ing to ex­plore a quirky Caribbean Is­land (about the size of Mas­sachusetts, New Hamp­shire, and Ver­mont put to­gether) should con­sider Lu­peron as an ex­cel­lent stag­ing point. Res­i­dent ex-pat cruis­ers will watch your boat while you ex­plore the coun­try by rental car.

This photo shows the mul­ti­ple lev­els of high ground that are nec­es­sary to pro­tect­ing a hur­ri­cane hole an­chor­age.

A mo­to­ry­acht ties up to the man­groves in Lu­peron Har­bor.

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