The 2020 D’Abadie Tornado

Mere days after the 2020 Chase Village Tornado, Trinidad and Tobago recorded yet another tornado in North-Central Trinidad, mainly affecting Crescent Gardens, D’Abadie. T&T generally experiences a confirmed tornado touchdown once every 10-20 years. This has generally held true with the 2009 Caroni Plains Tornado, then the 2019 tornadoes in Cunupia and Port of Spain respectively.

As forecast, after an initially hot and sunny morning across Trinidad, daytime heating and orographic effects aided convergence and triggered the rapid development of a severe thunderstorm across North-Central Trinidad.

Around 3:00 PM, reports of funnel clouds began coming in as it was spotted from Arouca and Arima. By 3:15 PM, reports and video of swirling debris began to circulate on social media. This coincided with torrential rainfall, street, and flash flooding, mainly in Arouca and Tacarigua while pea-sized hail was reported in Piarco.

These showers and thunderstorms dumped very localized amounts of rainfall, causing street and flash flooding mainly in Arouca.

How Did the Tornado Form?

A deep-layered low-pressure system, Invest 94L north of the Lesser Antilles has weakened the pressure gradient across the region, allowing for near calm to light and variable (direction) winds. A surface to low-level trough extended southwestward from the disturbance’s low-level center causing near calm winds across T&T through the morning, with winds even becoming southerly and westerly at times. At Piarco International Airport, at 3:00 PM, the time of the funnel cloud, winds were from the west-southwest to the west, instead of our usual easterly winds.

2:00 PM Sunday 18th October 2020 Surface Analysis from the Tropical Prediction Center
2:00 PM Sunday 18th October 2020 Surface Analysis from the Tropical Prediction Center.

In addition, strong daytime heating occurred across Trinidad. At Piarco, a maximum high of 35.5°C was recorded, making it the hottest day across Trinidad for 2020 to date.

Across Trinidad, by the late morning through the afternoon, light winds, daytime heating, and sea breeze convergence acted as triggers for shower and thunderstorm development, with orographic lift triggering/enhancing showers along the foothills of the Northern Range.

While the atmosphere was not necessarily hostile, conditions certainly were not favorable for strong convection development. We saw this as strong northwesterly wind shear limited persisting deep convection, spreading upper-level clouds southeastward and quickly dissipating the thunderstorm.

The rapid development and dissipation of thunderstorms on the afternoon of Sunday 18th October 2020. White dots indicate lightning strikes, which lined up in areas that had the strongest updraft, as seen across North-Central Trinidad, where the 2020 D'Abadie Tornado occurred. (Weathernerds.org)
The rapid development and dissipation of thunderstorms on the afternoon of Sunday 18th October 2020. White dots indicate lightning strikes, which lined up in areas that had the strongest updraft, as seen across North-Central Trinidad, where the 2020 D’Abadie Tornado occurred. (Weathernerds.org)

Several atmospheric conditions needed to come together across North-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 2020 D’Abadie 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 2020 D’Abadie 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 2020 D’Abadie Tornado, it lasted generally less than a few minutes with localized damage.

The Funnel Cloud & Tornado

Around 3:00 PM, residents between Arouca and Arima spotted the funnel cloud across the D’Abadie and Mausica area. This funnel cloud persisted for several minutes, based on videos submitted to us.

By 3:15 PM, the intense rotating column of air associated with the funnel cloud (though the cloud did not explicitly extend to the ground) touched down. Note that sometimes that rapidly rotating column of air gets in contact with the ground *without* a funnel cloud touching down, for various reasons, which is known as a tornado without a funnel. We did see in one of the videos (above) dust and debris in the characteristic spiral pattern.

Reports from the Crescent Gardens area in D’Abadie are still sparce, but at least three homes have been afffected with roof damage reported. There is still no word on injuries. This will be updated in the coming hours/days.

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.

In Trinidad, our previous tornado activity tends to be weak, generally ranking at 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.

Hail in Piarco

Hail, while rare for Trinidad and Tobago, usually accompanies severe thunderstorms that produce the other rare weather – a tornado. Hail was reported across the Piarco area, including at the Piarco International Airport on Sunday afternoon. The hail sizes were generally pea-sized, so for those who aren’t outside, it mostly sounds like very heavy raindrops. Thankfully, there were no reports of hail-related damage.

Gusty Winds (The Downburst)

As quickly as the severe thunderstorm developed, it dissipated, producing a downburst across Tacarigua to Piarco. Sustained winds up to 50 KM/H were recorded, with higher gusts likely. This caused wind damage across several areas.

In Tacarigua, gusty winds ripped off a roof along St. Michael’s Road. In Paradise, Tacarigua, a strong wind gust brought debris flying through the air, causing property damage.

The Floods

Rainfall was highly localized across North-Central Trinidad, with the sole area that experienced significant flooding being Arouca, where flash floods have hit for the 8th time this year. Flooding occurred in the Five Rivers area, as well as along the Eastern Main Road. Flooding quickly subsided as rainfall ceased.

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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