Kalain Ho­sein

Me­te­o­rol­o­gist/Re­porter

kalain.ho­sein@guardian.co.tt

Swel­ter­ing heat across parts of Trinidad yes­ter­day end­ed abrupt­ly, as roar­ing thun­der, strong winds and tor­ren­tial rain left sev­er­al with­out roofs and elec­tric­i­ty. Among the many places af­fect­ed was the Caribbean Air­lines hangar at Pi­ar­co.

Short­ly af­ter mid­day, ac­cord­ing to satel­lite light­ning da­ta, a sin­gle iso­lat­ed thun­der­storm de­vel­oped across south-cen­tral Trinidad and rapid­ly strength­ened, pro­duc­ing over 100 light­ning strikes per five-minute in­ter­vals. Fre­quent light­ing of this mag­ni­tude is a hall­mark of se­vere thun­der­storm ac­tiv­i­ty. With­in 30 min­utes, dam­ag­ing gusty winds be­gan to sweep across parts of Gas­par­il­lo, in­clud­ing Bonne Aven­ture.

A nar­row area of heavy to vi­o­lent rain­fall and strong winds moved from Bonne Aven­ture to Tor­tu­ga, Preysal, Chick­land, Cunu­pia and Pi­ar­co be­fore the thun­der­storm dis­si­pat­ed.

Based on in­ci­dent re­ports from the Of­fice of Dis­as­ter Pre­pared­ness and Man­age­ment (ODPM) and the Cou­va/Tabaquite/Tal­paro Re­gion­al Cor­po­ra­tion (CT­TRC), there were over 11 re­ports of blown-off roofs, with the ma­jor­i­ty oc­cur­ring in Bonne Aven­ture, Gas­par­il­lo, in­clud­ing Sur­prise Av­enue, Bonne Aven­ture Road, Phekoo Trace, and near the Gas­par­il­lo Sec­ondary School.

At the sec­ondary school, a tree and mul­ti­ple branch­es fell on­to a teacher’s ve­hi­cle, while gal­vanised sheets were blown on­to a car at Bonne Aven­ture Trace.

As the thun­der­storm took an atyp­i­cal path, mov­ing north­ward across the west­ern half of Trinidad, so did the trail of de­struc­tion.

Wind gusts up to 50 kilo­me­tres per hour blew off roofs in Cou­va at In­di­an Trail Vil­lage, Cunu­pia at Wall Street, Madras Road, and downed trees at Presyal at Boodram Lane. A sign al­so fell on a ve­hi­cle at the cor­ner of the South­ern Main Road and Chin Chin Road, Cunu­pia. With­in the Tu­na­puna/Pi­ar­co Re­gion­al Cor­po­ra­tion, a roof was par­tial­ly blown off on­to elec­tric­i­ty lines in Pi­ar­co at Gold­en Grove Road and Arou­ca at Farm Road.

Mean­while, gusty winds al­so caused dam­age with­in the Pi­ar­co In­ter­na­tion­al Air­port. Caribbean Air­lines Lim­it­ed (CAL), in a me­dia re­lease, con­firmed high winds as­so­ci­at­ed with the ear­ly af­ter­noon thun­der­storms dis­placed “sev­er­al gal­vanised sheets on a sec­tion of Hangars 9 and 10 at its Pi­ar­co base”.

CAL added that there “were no in­juries, all per­son­nel were safe, and con­trac­tors con­duct­ed an on-site as­sess­ment and se­cured the loose sheets.”

What caused the se­vere thun­der­storm?

Sev­er­al fea­tures came to­geth­er yes­ter­day to sup­port this sin­gu­lar strong thun­der­storm, which has some­thing to do with the swel­ter­ing tem­per­a­tures. In­tense day­time heat­ing led air near the sur­face to warm rapid­ly and rise. How­ev­er, ris­ing was strongest along west­ern coastal Trinidad, where west­er­ly winds from the Gulf of Paria at the low­er lev­els of the at­mos­phere met with sur­face east­er­ly winds that are more typ­i­cal for T&T.

When these air­mass­es col­lide, show­ers and thun­der­storms usu­al­ly form along west­ern coastal Trinidad, as they did yes­ter­day, but what was atyp­i­cal was the in­flu­ence of Trop­i­cal Storm Philippe well north­east of the re­gion, al­low­ing a south­west­er­ly wind flow at the low to mid-lev­els of the at­mos­phere. These atyp­i­cal winds at the low to mid lev­els, as well as a dry mid-lev­el at­mos­phere, sup­port­ed an en­vi­ron­ment favourable for a down­burst.

What is a down­burst?

Down­bursts are pow­er­ful winds that de­scend from a thun­der­storm and spread out quick­ly once they hit the ground, caus­ing dam­age sim­i­lar to a weak tor­na­do.