Hurricanes hurricane Fran 1996 1 basics



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HURRICANES



Hurricane Fran 1996
-1 BASICS

A hurricane is a type of tropical cyclone. In the Northern Hemisphere, there is a counterclockwise circulation of winds. Hurricane winds blow in a large spiral around a relative calm center known as the "eye." The "eye" is generally 20 to 30 miles wide, and the storm may extend outward 400 miles. They are low-pressure systems. The eye of a hurricane is always a low-pressure area. The lowest barometric pressures ever recorded have occurred inside hurricanes.

Tropical cyclones are classified as follows:

Tropical Depression: winds of 38 mph.

Tropical Storm: winds of 39-73 mph.

Hurricane: winds of 74 mph or higher (120km/h).

Hurricane-like storms are called by different names in the different regions of the world. For example, the name "hurricane" is given to systems that develop over the Atlantic or the eastern Pacific Oceans. In the western North Pacific and Philippines, these systems are called "typhoons" while in the Indian and South Pacific Ocean, they are called "cyclones".





-2 FORMATION

The ingredients for a hurricane include warm tropical oceans, moisture, wind. They can combine to produce violent wind, incredible waves, torrential rain, and floods. Most Atlantic hurricanes begin off the west coast of Africa, starting as thunderstorms that move out over the warm, tropical ocean waters. The ocean water itself must be warmer than 26.5 degrees Celsius (81°F). The heat and moisture from this warm water is the source of energy for hurricanes. They will weaken rapidly when they travel over land or colder ocean waters. Nevertheless a hurricane can extend inland for hundreds of miles.

August and September are peak months during the hurricane season that lasts from June 1 to November 30.

Hurricanes can spawn tornadoes

Floods are generated by torrential rains. They also cause damage and loss of life.

Inland streams and rivers can flood and trigger landslides

Even more dangerous than the high winds of a hurricane is the storm surge-a dome of ocean water that can be 20 feet at its peak and 50 to 100 miles wide. The surge can devastate coastal communities as it sweeps ashore. Nine out of 10 hurricane fatalities are attributable to the storm surge.

Each year, an average of ten tropical storms develop over the Atlantic Ocean. Many of these remain over the ocean and never impact the U.S. coastline. Six of these storms become hurricanes each year. In an average 3-year period, roughly five hurricanes strike the US coastline, killing approximately 50 to 100 people anywhere from Texas to Maine.Of these, two are typically "major" or "intense" hurricanes (a category 3 or higher storm on the Saffir-Simpson Hurricane Scale.

If one percent of the energy in one hurricane could be captured, all the power, fuel, and heating requirements of the United States could be met for an entire year.



-3 CLASSIFICATION AND DAMAGE

Saffir-Simpson Hurricane Scale


Category

Wind Speed

Effects

1

74 to 95 mph
(119 to 1

  • Storm surge 4 to 5 ft (1.2 to 1.5 m) above normal

  • Some flooding

  • No real damage to buildings.

2

96 to 110 mph
(155 to 1

  • Storm surge 6 to 8 ft (1.8 to 2.4 m) above normal

  • Trees down

  • Roof damage

  • Small boats grounded

3

111 to 130 mph
(178.6 to

  • Storm surge 9 to 12 ft (2.7 to 3.7 m) above normal

  • Structural damage in houses (damaged by floating debris).

  • Mobile homes destroyed

  • Severe flooding

4

131 to 154 mph
(210 to 2

  • Storm surge 13 to 18 ft (4 to 5.5 m) above normal

  • Severe flooding inland

  • Some roofs ripped off

  • Major structural damage

  • Major erosion of beach areas.

5

>155 mph
(> 249.4

  • Storm surge at least 18 ft (5.5 m) above normal

  • Severe flooding further inland

  • Serious damage to most wooden structures.

  • Flooding causes major damage to lower floors in houses ine.

  • Massive evacuation of residential areas may be required.



In a hurricane, the most violent winds occur in the area immediately around the eye. Hurricanes produce significant damage and loss of life, mainly due to flooding. When hurricanes move onto land, they can damage buildings, trees and cars. The heavy waves are called a storm surge. Storm surge is very dangerous and a major reason why you MUST stay away from the ocean during a hurricane warning. The storm surge acts like a bulldozer sweeping away everything in its path. The stronger the hurricane the higher the storm surge will be.

Be sure to ask family members, friends and neighbours if they are HURRICANE AWARE.



-4 HURRICANE PREPAREDENESS

Being hurricane smart means knowing what to do and having a safe place to go.

The key to hurricane protection is preparation. Preparation through education is less costly than learning through tragedy.
You may want to talk with your neighbours to coordinate preparation plans and help each other out.
Before hurricane season


  • Plan an evacuation route or , if you’re staying, determine the safest place in your home — an interior room, a hallway. Never decide to stay in a mobile home.




  • Don't be in a room with windows that can be broken.

  • If your house doesn't have a windowless room, you should at least stay under a table or behind a sofa.

Once a window is broken, the wind blows inside to not only wreck the interior, but also to apply upward pressure on the roof, which might be enough to send it flying. If this happens, the walls collapse and your house is flattened. Permanent shutters are the best protection.

  • Have an evacuation or survival kit ready with nonperishable food, water, a first aid kit and other things you'll need: cash and credit cards, and do not forget your insurance policy!! You may need it!!

  • Make arrangements for pets. Pets may not be allowed into emergency shelters for health and space reasons.

  • Take “before” pictures of your home for insurance claims.

  • Teach family members how and when to turn off gas, electricity, and water.



During a hurricane watch/ warning

  • Have a battery-powered radio (to get the latest news).

  • Evacuate early if you live in a mobile home (to avoid traffic).

  • Fuel car.

  • Bring in outdoor objects such as lawn furniture, toys, garden tools, mailbox and your garbage can (rubbish bin). The greatest threat to your home in most hurricanes is not the wind itself but wind-blown debris that can break windows and doors.

  • Remove outside antennas or satellite dishes.

  • Turn refrigerator and freezer to coldest settings. Open only when absolutely necessary.

  • secure boat.

  • Reinforce the garage doors.

  • Park your car where it will be most protected if it must be outdoors



During the hurricane
At this stage your main priority is to remain calm and out of danger. Outside your shelter raging winds are blowing torrential rain and battering your town. There is no reason, unless in an absolute emergency, that one would need to venture outdoors. Local officials have the authority to close roads and bridges.

Tips/Precautions:

• Stay indoors and away from windows.

• Stay tuned to radio (or TV if available) for weather bulletins.

• Use flashlights as a source of light.

• Candles can easily become a fire hazard

• Listen to local authorities.



° Avoid elevators (lifts)

After the hurricane

  • Take pictures of the damage for insurance claims.

  • Drive only if absolutely necessary and avoid flooded roads.

  • Check for gas leaks.

  • Look for electrical system damage.

  • Check for sewage and water lines damage.


-5 NAMING AND FORECASTING

To better track hurricanes, weather officials decided to name them.

Until World War II, hurricanes were given only masculine names. In the early 1950s, weather services began naming storms alphabetically and with only feminine names. By the late 1970s, this practice was replaced with alternating masculine and feminine names. The first hurricane of the season is given a name starting with the letter A, the second with the letter B and so on. According to NOAA, "the name lists... have an international flavor because hurricanes affect other nations and are tracked by the public and weather services of many countries."

Hurricanes in the Pacific Ocean are assigned a different set of names than Atlantic storms.




In the early part of this century, coastal residents used to have less than a day to prepare or evacuate their homes from an oncoming hurricane. Today, these same locations receive warnings to evacuate from one to two days in advance, let alone the extra days they are also aware of its existence. Before satellites and radars, people had very little knowledge of the weather just 100 kilometers offshore.


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