Severe Weather

Severe weather is no stranger to Trinidad and Tobago. Severe weather, according to the World Meteorological Organization, refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life.

Trinidad and Tobago is a very vulnerable country to several types of hydro-geological and meteorological hazards. These include:

High Winds

High winds are a year-round hazard for Trinidad and Tobago, and are known to cause damage depending on its strength. Wind speeds as low as 43 KM/H, a strong breeze on the Beaufort scale, can lead to power outages.

Wind Impacts on Land According to the Beauford Scale

Tropical storm and hurricane force winds, caused by individual severe thunderstorms, tornadoes or tropical cyclones can destroy roofs, entire homes which are poorly built and cause structural damage to homes with foundations.

When winds exceed 250 KM/H, which has not been recorded in Trinidad and Tobago in modern history but has occurred in neighbouring Caribbean islands, homes completely collapse, and significant damage is done to larger buildings. At even higher winds of 324 KM/H seen in strong hurricanes (or typhoons in the Pacific) as well as strong tornadoes, there is total destruction to man-made structures. For classifying these extreme winds, meteorologists use the Saffir-Simpson Wind Scale for tropical cyclones and the Enhanced Fujita Scale for Tornado Damage for tornadoes.

Tornadoes, Waterspouts & Funnel Clouds

Tornadoes, waterspouts and funnel clouds are intense columnar vortices in the shape of funnels with very strong winds and very low pressure near the center. These features usually develop from intense thunderstorms and are severe localized phenomena which may be accompanied by heavy rain or severe squalls. You can read more about these meteorological hazards here:

Warrenville Funnel Cloud on August 9th 2009.

Tornadoes are the least frequent of the three phenomena across Trinidad and Tobago, with one report of a confirmed tornado every 10-20 years, usually across Central and Western Trinidad. Waterspouts and funnel clouds are not uncommon across Trinidad, and are usually seen off Trinidad’s Eastern and Western Coasts. These features are seen several times a year as severe thunderstorms approach Trinidad from the East, or intensifying thunderstorms moving into the Gulf of Paria. There are nearly no accounts of any tornado, waterspout or funnel cloud sightings from Tobago.

Tropical Cyclones

Tropical Storm Don of 2017 as it approached the Southern Windwards.

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. It is generically used for tropical depressions, tropical storms or hurricanes (in the Atlantic and East/Central Pacific Basins).

An explanation of the types of tropical cyclones in the Atlantic Basin as well as the Saffir-Simpson Hurricane Wind Scale.

Hail

Any form of thunderstorm that produces precipitating hailstones is known as a hailstorm. Hailstorms are generally capable of developing in any geographic area where thunderclouds (cumulonimbus) are present, although they are most frequent in tropical and monsoon regions. The updrafts and downdrafts within cumulonimbus clouds cause water molecules to freeze and solidify, creating hailstones and other forms of solid precipitation. Due to their larger density, these hailstones become heavy enough to overcome the density of the cloud and fall towards the ground. The downdrafts in cumulonimbus clouds can also cause increases in the speed of the falling hailstones. The term “hailstorm” is usually used to describe the existence of significant quantities or size of hailstones.

Diagram explaining hail formation within a thunderstorm. (Credit: Encyclopedia Britannica, Inc.)

Hailstones can cause serious damage, notably to automobiles, aircraft, skylights, glass-roofed structures, livestock, and crops. Rarely, massive hailstones have been known to cause concussions or fatal head trauma. Hailstorms have been the cause of costly and deadly events throughout history. However, in Trinidad and Tobago, hail is rare.

Flooding

Flooding happens when the inflow of water into an area is faster than the outflow. In Trinidad and Tobago the following types of floods may occur. While flooding can, and do, occur year-round, during the rainy season, weather associated with the ITCZ and Tropical Waves tend to increase the frequency of flooding events.

Although floods may be categorized differently, one category may merge into another. The 3 main types of flooding that affect Trinidad and Tobago are:

Flooding across the Penal area during the floods of November 2018

You can read more about flooding in Trinidad and Tobago here:

Hazardous Seas

Throughout the year, Trinidad and Tobago experiences rough sea conditions for a multitude of reasons. These rough seas not only impact the lives or mariners but can translate into hazardous conditions near shore along bays and beaches and can even contribute to coastal flooding and erosion. You can read more about hazardous seas here:

Landslides

Landslides or landslips, mudslides, mud slips or mudflows, debris slides or debris slips and rockfalls, while all have some differences from one another, all reference a form of movement of sediment, rock or debris downslope due to gravity. Generally, a landslide/landslip is the general term for a wide variety of processes and landforms involving the downslope movement, under gravity, of masses of soil and rock material.

Landslides, unlike hurricanes, do not have a season for its occurrence. However, in years that are predominantly wet such as 2017, landslides occur at a higher frequency along the Northern Range. This is likely due to groundwater pressure destabilizing the slope. You can read more about landslides here:

Landslide Types

Heat Waves (Hot Spells)

In general, a heat wave is generally defined as a prolonged period with excessive heat. In Trinidad and Tobago, hot spell advisories (whether that be alerts, watches or warnings) are triggered when the Trinidad and Tobago Meteorological Service forecasts that there is a prolonged period for maximum temperatures being 33.0˚C or higher, on at least 3-5 consecutive days and the intervening nights to have a minimum temperature above 22.0˚C.

Although heat waves do not cause as much economic damage as other types of severe weather, they are extremely dangerous to humans and animals: according to the United States National Weather Service, the average total number of heat-related fatalities each year is higher than the combined total fatalities for floods, tornadoes, lightning strikes, and hurricanes. As in droughts, plants can also be severely affected by heat waves (which are often accompanied by dry conditions) can cause plants to lose their moisture and die. Heat waves are often more severe when combined with high humidity, as is the case in Trinidad and Tobago.

Drought

Another form of severe weather is drought, which is a prolonged period of persistently dry weather (that is, absence of precipitation). Although droughts do not develop or progress as quickly as other forms of severe weather, their effects can be just as deadly; in fact, droughts are classified and measured based upon these effects. Droughts have a variety of severe effects; they can cause crops to fail, and they can severely deplete water resources, sometimes interfering with human life.[88] In addition to the other severe effects, the dry conditions caused by droughts also significantly increase the risk of wildfires/bushfires.

According to the ODPM, Trinidad and Tobago has been victim to this naturally occurring phenomenon in the past. Most recently the country experienced severe drought in the last three months of 2009 extending into the first quarter of 2010. Here rainfall was about 25% of what was expected given historical averages. This drought episode was also accompanied by severe forest fires, incidences of crop failure and flash flooding during some spells of post-drought rainfall. In Trinidad and Tobago drought conditions were also recently evident in 1997-1998 and from 2002-2004.

Fires

According to the ODPM, In Trinidad and Tobago, forest fires (also commonly referred to as bush fires or wild fires) are signature events of the dry season. Annually throughout the country, especially along hillsides and roadways, these hazards leave a discernable mark on the biological landscape.

Forest fires can be natural occurrences, however, each year, incidences of natural forest fires are augmented by occurrences of fires set deliberately or inadvertently by humans. Out of control ‘slash and burn’ agricultural practices, hunters lighting areas to flush animals out of hiding places and careless tossing of cigarettes out of car windows are common ways in which anthropogenic forest fires can result. It is important to note, however, that in the context of forest fires as hazards, a distinction should be drawn between forest fires and prescribed burns i.e. those fires intentionally set and controlled by environmental experts in order to actively manage a particular habitat.

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