The 2009 Caroni Plains Tornado

Like out of a movie, a rare tornado touched down in the Caroni Plains on August 9th, 2009. Between 12:30 PM and 2:00 PM that Sunday afternoon, a severe supercell thunderstorm formed.

This thunderstorm produced a tornado between Warrenville and Charlieville on the Caroni Plains and localized heavy to violent rainfall. There were even reported of hail in Cunupia.

Though no severe damage was reported as a direct result of the tornado, heavy showers, and additional thunderstorms, due to favorable atmospheric dynamics, produced street and flash flooding across parts of Trinidad.

How Did the Tornado Form?

A tropical wave moved across the region earlier that day on Sunday 9th August 2009. Unusually light winds were recorded across Trinidad, with near calm to calm conditions prevailing across Central Trinidad. Prevailing winds at low-levels were generally from the southwest to southeast due to the tropical wave location.

8:00 AM Surface Analysis from the Tropical Prediction Center.
8:00 AM August 9th 2009 Surface Analysis from the Tropical Prediction Center.

This light winds and increased atmospheric moisture from the ITCZ across the islands allowed daytime heating and sea breeze convergence to act as a trigger for convective activity.

Several atmospheric conditions needed to come together across Central Trinidad for this rare phenomenon to form.

Tornado formation is not completely understood and there are two main ways a tornado may form. In the case of the 2009 Caroni Plains tornado, the below mechanism is the likely explanation for how this tornado formed.

Firstly, a horizontal spinning effect must form on the Earth’s surface. This usually originates in sudden changes in wind direction or speed, known as wind shear. Secondly, a thundercloud, or occasionally a cumulus cloud, must be present.

A diagram showing the formation of a tornado
The mechanism for the formation of the 2009 Caroni Plains Tornado.

During a thunderstorm, updrafts are occasionally powerful enough to lift the horizontal spinning row of air upwards, turning it into a vertical air column. This vertical air column then becomes the basic structure for the tornado. Tornadoes that form in this way are often weak and generally last less than 10 minutes.

In the case of the 2009 Caroni Plains Tornado, it lasted generally 15-20 minutes and minimal damage occurred.

Who was impacted?

1:15 PM to 1:45 PM Sunday 9th August 2009 Radar Imagery showing the supercell thunderstorm that produced the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.
1:15 PM to 1:45 PM Sunday 9th August 2009 Radar Imagery showing the supercell thunderstorm that produced the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.

Eye­wit­ness­es said they saw a long, slen­der, fun­nel-like cloud in the sky just around 12.30 pm. “It was twirling around some­thing that looked like a thick black ca­ble,” said Aman­da Khan, who record­ed the im­age on her cell­phone from her Cunu­pia home. She said vil­lagers came out of their homes and looked on in amaze­ment at the phe­nom­e­non, some even won­der­ing if the tor­na­do would hit their homes.

Trinidad Guardian, Sunday 9th August 2009.

The Tornado

This tornado was spotted from Charlieville, Warren, Warrenville, Cunupia and St. Helena/Caroni. Thankfully, this weak, short-lived tornado stayed across agricultural areas of the Caroni Plains. However, there were reports of wind damage to Sheik Lisha Ltd on South­ern Main Road. Winds ripped galvanize sheets off the roof of the business place.

Tornadoes are generally rated on a damage-based scale called the Enhanced Fujita Scale in the United States and Canada, though other regions have different tornado scales. This scale uses the damage (or lack thereof) to rate the wind speeds of the tornado after the event.

Based on details of this tornado, we would rank this as an EF-0 tornado. With an EF-0 tornado, winds between 105 KM/H to 137 KM/H occur. Damage typical for this scale of a tornado is a peeled off surface from some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over.

Note that confirmed tornadoes with no reported damage (i.e., those that remain in open fields) are always rated EF0.

Note that there was one media report from CNC3 stating that there were two tornadoes, but based on radar data and ground reports, there was only one. This “second” tornado may have been due to persons on the ground seeing the same tornado from different vantage points.

Other Inclement Weather

1:45 PM Sunday 9th August 2009 Radar Imagery showing the supercell thunderstorm that produced the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.
1:45 PM Sunday 9th August 2009 Radar Imagery showing the supercell thunderstorm that produced the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.
Cross-section of the above radar image, showing an area (under C) where rainfall rates would have neared or exceeded 167 millimeters per hour resulting from the supercell that triggered the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.
Cross-section of the above radar image, showing an area (under C) where rainfall rates would have neared or exceeded 167 millimeters per hour resulting from the supercell that triggered the 2009 Caroni Plains Tornado. Imagery: Trinidad and Tobago Meteorological Service.

This supercell thunderstorm was part of a multi-day heavy rainfall event across Trinidad and Tobago due to the passage of a tropical wave on Saturday 8th August 2009 into Sunday 9th August 2009. In addition, the ITCZ remained across the region with favorable atmospheric dynamics in place.

Heavy to violent rainfall rates, up to 200 millimeters per hour occurred across parts of Chaguanas, Chase Village, Charlieville, Endeavour, Warrenville and surrounding areas. Residents in Cunupia even reported experiencing small hailstones, which is not uncommon with supercell thunderstorms.

This supercell thunderstorm, combined with other showers and thunderstorms on Sunday 9th August 2009 triggered street and flash flooding across Western and Northern Trinidad.

Parts of Chase Village, Freeport and Chaguanas reported heavy rains, strong winds and street flooding.

Straight-Line Winds, Flash Flooding in Rio Claro

Gusty winds associated with another thunderstorm across southeastern Trinidad blew off 8 roofs at Mahabalsingh Trace, Rio Claro. 45 persons had to seek temporary shelter with other family members. T&TEC temporarily switched off power to the area to prevent electrical fires. Note that this was due to strong straight-line winds and not another tornado.

Flash flooding cut off Mahabalsingh Trace from the Cunapo Southern Main Road and vehicular traffic slowed significantly as drivers drove on the submerged roads.

Street & Flash Flooding Elsewhere

Flooding from Saturday was exacerbated by rainfall on Sunday. Parts of Seurdage Trace, Penal and Khanai Trace, Barrackpore remained under floodwaters impacting several homes in the area.

Parts of Inverness Road, Princes Town, Claxton Bay, and Couva were also impacted by flooding.

Note that this inclement weather began on August 8th and continued through August 10th, triggering severe street and flash flooding across much of Trinidad. This was due to back to back tropical waves, the ITCZ remaining across the region, as well as favorable atmospheric dynamics allowing daytime heating, orographic precipitation, and sea breeze convergence to affect the islands.

Reports were compiled from the Trinidad and Tobago Newsday and the Trinidad Guardian.

How Frequently Does T&T Experience Tornadoes?

This is a difficult question to answer, as there really has been no good (or at least public) record-keeping of tornado events across Trinidad and Tobago.

It’s even more difficult to ascertain what exactly was a tornado versus the more common straight-line winds across Trinidad. Media reports and the general public usually attributes major wind damage to “twister-like” or “tornado-like” events.

Nine times out of ten, wind damage across Trinidad and Tobago can be attributed to gusty winds from thunderstorms or straight-line winds.

However, we’re trying to build a database of these events, by scouring media reports dating back to the early 1900s to come up with how frequently these events occur and where have they occurred in the past.

Tornadoes across Trinidad and Tobago remain a very rare feature, but due to a lack of technology to issue and disseminate timely warnings to the public, it is imperative you know what to do in the event one occurs.

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