Natural Hazards, Disasters, and Hurricanes

Vocabulary practice flashcards covering natural and technological hazards, vulnerability and risk calculations, hurricane formation stages, meteorological structure, the Saffir-Simpson scale, historic Caribbean case studies, and disaster mitigation strategies.

Compass Bearing

The angular direction measured in degrees clockwise from North ($350^\circ\text{--}10^\circ$ or $360^\circ$), including primary headings such as East ($80^\circ\text{--}100^\circ$), South ($170^\circ\text{--}190^\circ$), and West ($259^\circ\text{--}280^\circ$).

Hazard

Any phenomenon or event that has the potential to cause harm; divided into natural and man-made (technological) categories.

Natural Hazard

Any event created through the forces of nature, being a spontaneous atmospheric, climatic, or physical phenomenon not caused by man that has the potential to cause loss of life and property.

Seismic Hazards

Earth-movement hazards that include earthquakes, liquefaction ground failure, and volcanoes.

Geomorphological Hazards

Hazards related to mass movement of the earth, including landslides and mud flows.

Biological Hazards

Hazards caused by biological agents or organic processes, including epidemics, human diseases, and forest, bush, and grass fires.

Disaster

The aftermath of a hazard; the resulting impact and level of destruction that occurs on man and his environment after a hazard has struck a region or island.

Disaster Criteria

Specific thresholds indicating a disaster event: $10$ or more people killed, $100$ people reported affected, a call made for international assistance, or more than $5$ days spent without basic necessities.

Vulnerability

The characteristics and circumstances of a community that make it susceptible to the damaging effects of a hazard, such as poor design and construction of buildings, inadequate protection of assets, and lack of public information and awareness.

Risk

The potential disaster that could occur to a particular community or society over a specified future time period, calculated by the formula: $\text{Risk} = \text{Probability of Hazard} \times \text{Degree of Vulnerability}$.

Hurricane

An intense tropical weather system consisting of a well-defined eye and strong winds exceeding $120\,\text{km/h}$ with atmospheric pressure less than $990\,\text{mb}$, blowing anticlockwise in the Northern Hemisphere, spanning about $1000\,\text{km}$ in diameter, and occurring from June to November.

Easterly Wave (Stage 1)

The initial stage of hurricane development consisting of a trough or belt of low pressure ($1016\,\text{mb}$) over tropical areas, accompanied by heavy rain, cumulus and thick cumulonimbus clouds, thunderstorms, and wind speeds between $15\text{--}20\,\text{km/h}$.

Tropical Depression (Stage 2)

A developing system that is not a fully developed cyclone and lacks an eye, characterized by low pressure ($1005\text{--}1010\,\text{mb}$), heavy rain, thunderstorms, and winds blowing anticlockwise at $\sim 62\,\text{km/h}$ or less.

Tropical Storm (Stage 3)

An intense weather system with low pressure ($990\text{--}1000\,\text{mb}$), a developed centre or eye, torrential rain, and anticlockwise rotary winds with speeds between $63\,\text{km/h}\text{--}119\,\text{km/h}$.

Saffir-Simpson Scale

A $1\text{--}5$ category rating scale used to measure the extent of hurricane impact and potential damage based on sustained wind speeds, with Category $5$ causing the greatest damage.

World Meteorological Organization (WMO)

The international organization responsible for naming Atlantic hurricanes and tropical storms.

Ahead of the Hurricane ($70\text{--}100\,\text{km}$)

The zone where weather is calm with gentle winds from the North, high humidity, hot and sticky air, pressure falling to $1006\,\text{mb}$, cumulus clouds forming, and showers beginning to develop.

Front of the Vortex ($30\text{--}50\,\text{km}$)

The forward wall of the hurricane where pressure and temperatures fall rapidly, wind speeds exceed $100\,\text{km/h}$ blowing from the North West, and cumulonimbus clouds produce thunder and torrential rain of up to $250\,\text{mm/day}$.

Eye of the Hurricane ($15\text{--}50\,\text{km}$)

The calm central core of the hurricane characterized by light winds of $10\text{--}20\,\text{km/h}$, low pressure ($985\,\text{mb}$), little or no rain, brief appearances of the sun, and temperatures approximately $2^\circ\text{C}$ higher than the rest of the storm.

Back of the Vortex ($30\text{--}50\,\text{km}$)

The trailing wall of the storm where torrential rain and winds over $100\,\text{km/h}$ resume from the opposite direction (South East), temperature drops to $28^\circ\text{C}$, and pressure begins rising toward $1010\,\text{mb}$.

Storm Surge

A large dome of water extending about $80\text{--}100\,\text{km}$ wide and up to $6\,\text{m}$ high that sweeps ashore as a hurricane approaches; considered the chief cause of loss of life and a major source of property damage in hurricanes.

Types of Floods

The four main classifications of flooding caused by hurricane rainfall: coastal, urban, riverine, and flash flooding.

Hurricane Ivan (2004)

A Category $4$ hurricane in September 2004 that caused $70$ deaths in the Caribbean, destroyed $90\%$ of homes and $90\%$ of nutmeg, coffee, and banana crops in Grenada, damaged $75$ out of $77$ Grenadian schools, and devastated Negril, Jamaica.

Hurricane Maria (2017)

A Category $5$ hurricane occurring in September–October 2017 that resulted in $3059$ deaths (including $2975$ in Puerto Rico and $65$ in Dominica) and an overall damage cost of $\text{US}\,\$96.1\,\text{B}$.

Roof Gradient (Mitigation)

A structural building standard recommending a roof slope of $30^\circ$ secured with hurricane straps to minimize wind-lifting forces during a hurricane.

Hurricane Watch

An early alert issued when hurricane conditions are likely within the next $36$ hours, instructing residents to prepare, batten windows, and assemble emergency supplies.

Hurricane Warning

An urgent alert issued when hurricane conditions are expected within $12\text{--}24$ hours, indicating that residents must take immediate action to evacuate low-lying areas or seek shelter.

ODPEM

The Office of Disaster Preparedness and Emergency Management; coordinates an inter-agency network within the country to maximize life preservation and property protection during disasters.

NOAA Hurricane Hunters Aircraft

Specialized reconnaissance aircraft that fly directly into the centre of a hurricane to gather real-time data on wind speed, barometric pressure, temperature, and humidity.

Emergency Relief Numbers (Trinidad & Tobago)

Specific response hotlines including Police Rapid Response ($999$), Fire Service ($990$), Tobago Emergency Relief ($211$), Global Medical Response of Trinidad and Tobago / GMRTT ($811$), and Crime Stoppers ($800\,\text{TIPS}$ / $8477$).