Hurricanes

What defines a Hurricane?

A Hurricane is a formidable cyclonic (rotating) tempest boasting maximum sustained winds of 74 miles per hour (119 km per hour) or greater.

• Typhoons are their Pacific counterparts, while cyclones denote them in the Indian Ocean. Their genesis occurs over balmy seas and oceans, stemming from atmospheric disruptions like tropical waves. For a hurricane to materialize, the surface temperature of the surrounding body of water must reach a minimum of 27 degrees Celsius.

The Development of a Hurricane: Four Stages

The development of a hurricane can be divided into FOUR primary stages.

1. Tropical Disturbance - This marks the initial formation of a hurricane, characterized by a slight circulation without closed isobars surrounding a region of low pressure. Typically found within the tropical trade winds, tropical disturbances frequently bring along clouds and precipitation.
2. Tropical Depression - A tropical depression is characterized by a closed circulation, indicating an area of low pressure (approximately 1005-1010 mb), where winds converge. Within a tropical depression, the maximum sustained wind speed reaches 38 miles per hour/62 km per hour.
3. Tropical Storm - Under the appropriate circumstances, a tropical depression has the potential to transform into a tropical storm. To meet the classification of a tropical storm, the sustained winds must reach a minimum speed of 39 miles per hour / 63 km per hour. Typically, the atmospheric pressure ranges from 990 mb to 1000 mb within a tropical storm. Once a system attains tropical storm status, it is assigned a name from a predetermined roster.
4. Assuming conditions remain favorable, a tropical storm will progressively intensify until it reaches hurricane status, defined by sustained winds reaching 74 miles per hour (119 km per hour). The potential for further strengthening exists, allowing hurricanes to attain significantly higher sustained wind speeds. As a hurricane strengthens, the atmospheric pressure within it drops below 990 mb. The peak intensity of Hurricane Wilma in October 2005 witnessed the lowest ever recorded atmospheric pressure for an Atlantic hurricane, measuring at 882 mb.

Hurricane Classification

To classify hurricanes, the Saffir-Simpson Hurricane Wind Scale employs five categories. Here is an outline of the classification:

Category 1: Hurricanes have sustained winds ranging from 74-95 mph or 119-153 km per hour.

These hurricanes present a notable hazard as they cause damage to well-constructed frame homes, including roofs, shingles, vinyl siding, and gutters. Moreover, large tree branches are susceptible to snapping, and shallow-rooted trees may be uprooted. Power lines and poles are highly likely to experience extensive damage, resulting in power outages that could persist for a few to several days.

Category 2 hurricanes are characterized by sustained winds ranging from 96 to 110 mph or 154 to 177 km per hour. These hurricanes possess winds of an exceedingly hazardous nature, leading to widespread destruction. Well-built houses with sturdy frameworks may experience significant damage to their roofs and siding. Additionally, a large number of trees with shallow root systems are expected to be either broken or uprooted, resulting in the obstruction of numerous roads. Furthermore, extensive power outages are anticipated, with the possibility of prolonged disruptions lasting from several days to weeks.

Category 3 hurricanes, characterized by sustained winds ranging from 111-129 mph or 178-208 km per hour, bring about significant consequences. Substantial destruction is expected, including severe damage or complete removal of roof decking and gable ends for well-built framed homes. Numerous roads will be blocked as a result of numerous snapped or uprooted trees. The availability of electricity and water will be disrupted for a period of several days to weeks following the passage of the storm.

Category 4 hurricanes, characterized by sustained winds of 130-156 mph or 209-251 km per hour, bring about catastrophic consequences. Well-constructed framed houses are at risk of severe damage, including significant loss of roof structure and/or exterior walls. The majority of trees will either snap or be uprooted, and power poles will be knocked down. This will result in residential areas being cut off due to fallen trees and power poles. Expect prolonged power outages lasting anywhere from weeks to potentially months. The affected region will be rendered uninhabitable for weeks or even months.

Category 5 hurricanes exhibit sustained winds reaching or exceeding 157 mph (252 km per hour). Such hurricanes cause catastrophic devastation, resulting in the destruction of a significant number of framed homes, complete roof failures, and wall collapses. Furthermore, residential areas become isolated due to fallen trees and power poles, leading to prolonged power outages lasting for weeks or possibly months. The impacted region is expected to remain inhabitable for an extended duration, ranging from weeks to months.

The Atlantic Hurricane Naming Process

Every year, hurricanes emerge, occasionally with multiple simultaneous occurrences. The utilization of names for these storms greatly facilitates effective communication among meteorologists, researchers, emergency responders, ship captains, and the public when referring to specific hurricanes.

• Consequently, the World Meteorological Organization formulates a roster of names that are sequentially assigned to tropical storms as they are identified during each hurricane season. Names may be reused after six years, although names associated with exceptionally severe storms are permanently withdrawn from circulation.

The criteria for determining the names of hurricanes in the Atlantic Ocean, both recent and future ones, follow this structure: once a tropical storm reaches a sustained wind speed of 39 miles per hour, it is given a name such as "Tropical Storm Fran." If the storm's wind speed escalates to 74 miles per hour, it becomes classified as a hurricane and is known as "Hurricane Fran." Hence, tropical storms receive names which remain unchanged if they intensify into hurricanes. The Atlantic Storm Names table on this page provides the assigned names for both recent and upcoming storms.

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History of Atlantic Hurricane Names

• Names have been given to Atlantic hurricanes for a few hundred years. People living in the Caribbean Islands named storms after the saint of the day from the Roman Catholic liturgical calendar for the day on which the hurricane occurred such as "Hurricane San Felipe." When two hurricanes struck on the same date in different years, the hurricanes would be referred to by names such as "Hurricane San Felipe the first" and "Hurricane San Felipe the second."

Retired Hurricane Names

• The sole alteration made to the roster of Atlantic hurricane names occurs through the occasional retirement of a name. This step is taken when a hurricane inflicts significant loss of life and destruction, rendering the reuse of the same name insensitive to those who suffered losses. In such instances, the World Meteorological Organization substitutes the retired name. For instance, the name "Katrina" has been retired from the list and will not be utilized again.
• This webpage displays a compilation of hurricane names that have been retired since the establishment of the current name list system in 1979. Alongside retirements, a few names have been merely replaced. As an example, for the 2013 list, the names Dean, Felix, and Noel were substituted with Dorian, Fernand, and Nestor, respectively, from the 2007 list.

Identify the names of devastating hurricanes of the Caribbean

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Hurricane Gilbert

When Hurricane Gilbert struck as a category 5 hurricane in 1988, it became the most intense hurricane ever to hit the Atlantic Ocean. Hurricane Gilbert's wind speeds maxed out at 185 mph (298 KPH). It held this record until the current record holder, Hurricane Wilma, claimed its place in 2005. It was an extraordinarily large hurricane, spanning 925 km in diameter The Lesser Antilles, Puerto Rico, Venezuela, Haiti, Dominican Republic, Jamaica, Central America, Mexico and Texas were all affected by Hurricane Gilbert. It killed a total of 318 people and caused damages of almost 3 billion dollars. The destruction caused was so great, the hurricane name Gilbert was retired and Gordon was adopted in 1989.

Pathway of Hurricane Gilbert

Hurricane Sandy, regarded as the deadliest hurricane in 2012 and one of the most destructive in American history, struck the United States and caused a staggering $68.7 billion in damages from October 22 to November 2, 2012. With sustained winds reaching 115 mph (185 km/h), Sandy claimed the lives of 233 individuals. Initially, it wreaked havoc in the Caribbean, resulting in 75 fatalities, before progressing northward. As it neared the East Coast, Sandy generated unprecedented waves in the western Atlantic and unleashed a devastating storm surge and widespread flooding in coastal New York and New Jersey. Spanning approximately 800 miles between the East Coast and the Great Lakes region, the storm, also known as Superstorm Sandy, inflicted $70.2 billion in damages, left 8.5 million people without electricity, destroyed 650,000 homes, and caused numerous fatalities.

The trajectory taken by Hurricane Sandy.

The Effects of Hurricanes:

The primary dangers associated with hurricanes include:

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Storm Surge

When a hurricane makes landfall, it forcefully propels a large amount of ocean water onto the shore, resulting in what we refer to as a storm surge. This surge manifests as a gradual increase in the water level as the storm approaches. The duration of storm surge flooding varies depending on the hurricane's size and path. However, it typically subsides after the storm has passed. Water levels during a hurricane can exceed 20 feet above the usual sea level. When combined with powerful waves, a hurricane's storm surge has the potential to cause extensive devastation.

Powerful gusts

Winds with the strength of a hurricane, measuring 74 mph or higher, possess the ability to demolish structures and mobile homes. Items like signs, roofing material, siding, and small objects left outdoors transform into airborne projectiles amidst hurricane conditions. Even far inland, the winds may persist at intensities exceeding hurricane force. The sustained wind speeds can exceed 200 mph, contingent upon the hurricane's category. Furthermore, aside from the direct destructive impact of the winds, they also give rise to colossal waves and contribute to the storm surge.

Excessive precipitation

Excessive rainfall is a common occurrence during hurricanes, with the potential for heavy downpours exceeding 6 inches. This can lead to devastating floods that pose a significant threat, often resulting in loss of life and widespread destruction. For those residing inland, flooding becomes the primary concern associated with hurricanes. Rapid water level increases, known as flash flooding, can materialize swiftly due to intense rainfall. Moreover, the effects of heavy rainfall can persist for days after the storm as rivers and streams continue to flood.

The amount of rainfall experienced is not directly linked to the intensity of tropical cyclones. Rather, it depends on factors such as the storm's size, speed, and the geographical features of the affected region. Larger and slower-moving storms tend to generate higher levels of precipitation. Additionally, mountainous terrain exacerbates the rainfall associated with tropical cyclones.

These primary hazards have far-reaching implications, impacting the economy, society, and the environment, among other factors.

Christopher Seebaran (pc)

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