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Hurricanes and Tropical Storms
Q: What is the difference between a Tropical Disturbance, Tropical Depression, Tropical Storm and Hurricane?
We often hear reports about these atmospheric hazards, but what really differentiates one from the others?
A: The answer is intensity.
- A Tropical Disturbance is a discrete weather system of apparently organized convection, originating in the tropics or subtropics and existing for a period of over 24 hours .Disturbances are characteristically approximately 200-600 km in diameter.
- A Tropical Depression is a tropical cyclone displaying a closed circulation pattern, in which the maximum sustained wind speed reaches up to but does not exceed 17m/s.
- A Tropical Storm is also a tropical cyclone, but with faster winds speeds. Tropical cyclones are classified as tropical storms when the maximum sustained surface wind speed ranges between 17.5 m/s and 32.5 m/s.
- A Hurricane occurs when a tropical cyclone reaches or exceeds maximum sustained wind speeds of 33 m/s. Hurricanes can be further classified using the Saffir- Simpson Hurricane Wind Scale, which is a 1 -5 classification of the hurricanes intensity at the indicated time.
Q: When do hurricanes and tropical cyclones occur?
A: These hazards affect certain areas at different times during the season. The official Atlantic Hurricane Season extends from June 1st to November 30th, but Trinidad is most likely to be affected during the period of August to September, as seen in the maps below.
Map 1: Tropical Cyclone Tracks for August in the Caribbean. Source: NOAA
Map 2 : Tropical Cyclone Tracks for September in the Caribbean. Source: NOAA
Q: What is the difference between a Hurricane Watch and a Hurricane Warning?
A: The likelihood of occurrence.
- A Hurricane Watch is issued when hurricane conditions (maximum sustained winds of 33m/s or higher) are possible within a specified area. A watch is typically issued 48 hours prior to the anticipated hazard onset.
- A Hurricane Warning is issued when hurricane conditions are expected within a specified area. A warning is typically issued 36 hours prior to the anticipated hazard onset.
Q: Are we Vulnerable to Hurricanes and Tropical Cyclones?
Trinidad and Tobago is located in the extreme south of the Caribbean, a position which implies that the country is safe from the impacts of hurricanes and tropical cyclones. This however is not true. While in Trinidad and Tobago the risk to hurricanes is minimal when comparison to other islands in the Caribbean, the potential to be hit by hurricanes still remain, as they have in the past.
Q: What is vulnerable?
A: Both the population and the natural and built environment are vulnerable to the impacts of hurricanes and Tropical Storms.
Q: Are some areas more vulnerable than others?
Here are a few examples:
- Low lying areas: Intense rainfall associated with hurricanes and tropical cyclones can rigger flooding as a secondary hazard.
- Poorly constructed buildings: such as Squatter settlements. Strong winds are another characteristic of hurricanes and tropical cyclones and at times can become powerful enough to damage roofs and infrastructure such as electricity and telecommunication lines.
- Unstable Land: Intense rainfall can also trigger landslides as secondary hazards, this can affected settlements on slopes or on unstable soils.
Q: How can I reduce the impacts of Hurricanes and Tropical cyclones?
A: Be Prepared.
Adequate preparation can reduce and even prevent the impacts of hurricanes and tropical cyclones. Here are a few things you can do:
Prior to a hurricane
- Trim trees growing near electrical wires and telephone lines.
- Secure windows and doors; if possible acquire hurricane straps for the roof.
- Cleans drains and gutters regularly
- Avoid dumping garbage in rivers
- Prepare an emergency kit containing first aid items , battery operated radio, food and water for at least seven days , small tools such as plastic sheeting , gloves , flashlights etc
- Secure important documents such as passports, birth certificates, marriages certificates, exam cards etc. These should be stored ideally in a water proof bag at a safe location.
- Identify an alternative location for temporary stay in the event that evacuation is necessary, such as a family member or close friend. If no such place is found, then the nearest possible shelter location should be identified.
- Secure household items which may fall and break causing damage such as glass items and other sharp or heavy objects.
During a Hurricane
- Remain Calm
- Stay indoors away from windows
- Keep updated on the situation via radio/television/ internet
- After the Hurricane
- Ensure all members of your party (family) are accounted for; if someone is missing immediately contact the relevant authorities.
- Boil water unless you are told it’s safe.
- Stay clear of downed electricity lines, report to the relevant authorities
- Avoid /limit contact with flood waters
- Lend assistance to injured or special population such as children, elderly or differently able.
Further Reading :
- National Hurricane Center
- FEMA: Hurricane
- Hurricane Preparedness Checklists for Homes
- FAQ : Hurricanes, Typhoons, and Tropical Cyclones