Florida Hurricane Information

A hurricane is a tropical storm with winds that have reached a constant speed of at least 74 miles per hour. Hurricane winds blow in a large spiral around a relatively calm center known as the "eye". The eye is generally 20 to 30 miles wide and the storm may spread outward 400 miles. As a hurricane approaches land, it brings severe rain, wind and storm surges. August and September are peak months during the hurricane season, which generally lasts from June through November.

In this section you'll get to learn:

What is Hurricane? How are Hurricanes formed

Parts of Hurricane

Hurricane: Classifications

Basic Hurricane Safety Actions

Watch Vs Warning - Know the difference

Caught in a Hurricane?

Someother tips..!!

What is Hurricane?

The wind blows. The rain comes down. Hurricanes are powerful. They can rip a house apart. They can wipe out cities. But how do they start? And how do you know how big it will be?

Hurricanes start over the ocean. They need three things:
1. Warm water
2. Damp air
3. Winds that meet

When the wind blows at least 74 miles an hour, it is called a hurricane. That is very fast! It is faster than a car drives on a highway. Sometimes the winds blow faster than that.

The ingredients for a hurricane include a pre-existing weather disturbance, warm tropical oceans, moisture, and relatively light winds aloft. If the right conditions persist long enough, they can combine to produce the violent winds, incredible waves, torrential rains, and floods we associate with this phenomenon.

Each year, an average of ten tropical storms develop over the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. 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 hurricane is a type of tropical cyclone, which is a generic term for a low pressure system that generally forms in the tropics. The cyclone is accompanied by thunderstorms and, in the Northern Hemisphere, a counterclockwise circulation of winds near the earth's surface. Tropical cyclones are classified as follows:

Tropical Depression
An organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds* of 38 mph (33 kt**) or less

Tropical Storm
An organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds of 39-73 mph (34-63 kt)

Hurricane
An intense tropical weather system of strong thunderstorms with a well-defined surface circulation and maximum sustained winds of 74 mph (64 kt) or higher

* Sustained winds - A 1-minute average wind measured at about 33 ft (10 meters) above the surface.
** 1 knot = 1 nautical mile per hour or 1.15 statute miles per hour. Abbreviated as "kt".

Parts of a Hurricane

There are three main parts of a hurricane:

Eye -- This is the center. It is the calm part of the storm.

Eye Wall -- This part is around the eye. This part has the strongest winds and rains. The winds may blow 200 miles per hour.

Rain Bands -- These are the clouds that spin out and make the storm bigger.

Image above: Credit: NASA

Hurricane : Classifications

Hurricanes are rated using theSaffir Simpson Scale.This scale ranges from category 1 (weakest) to category 5 (strongest). This classification scheme can be used to give an estimate of the potential property damage and flooding expected along the coast from a hurricane. Below are the wind speeds assigned to each category

Category One: This type of hurricane is the least violent compared to the other categories. The storm surge is about 4-5 feet above normal. Usually there is no major damage to structures on land, except for mobile homes that may not be anchored to the ground. Vegetation, such as trees or shrubs, may be damaged. Some coastal flooding may occur. An example of this type of hurricane was Hurricane Danny in July of 1997. This hurricane hit land near the mouth of the Mississippi River and stalled over Mobile Bay, Alabama for about 15 hours. A very slow-moving hurricane, Danny created heavy rains in southern Alabama

Category Two: A hurricane in this category has wind speeds between 96 and 110 mph with a storm surge of about 6-8 feet above normal. Damage can occur to trees and/or shrubbery with some damage to certain roofing materials. Windows may also be damaged. Mobile homes and piers may especially be affected. Floods could be expected about two to four hours before the center, or eye, of the hurricane passes. An example of this type of hurricane was Hurricane Marilyn of 1995. This caused intense damage to portions of the U.S. Virgin Islands. The hurricane was almost at category three intensity when it came near the islands.

The winds blow at about 100 mph; it may break windows and destroy trees.

Category Three: With this type of hurricane, the sustained winds are from 111-130 mph, with a storm surge of about 9-12 feet above normal. Some structural damage could be expected, especially to smaller dwellings and buildings. Large trees may be blown down and mobile homes could be destroyed. Flooding could occur about 3-5 hours before the eye of the hurricane passes, especially in low-lying areas. Flooding could be extended over several miles. Low-lying areas may, in fact, be evacuated. Smaller structures on the coast could be destroyed and the debris may contribute to damage of larger buildings. In 1996, Hurricane Fran, which struck the North Carolina coastal area, was a category three hurricane. It caused extensive flooding and wind damage.

Category Four: This type of hurricane produces winds that are 131-155 mph, with a storm surge of about 13-18 feet above normal. Smaller residences and buildings may have complete roof failure, while mobile homes may be completely destroyed. Extensive damage to doors and windows of structures may be expected. Trees and shrubs could be blown down. About three to four hours before the hurricane center passes, flooding could be expected, and may cause extensive damage to the lower floors of buildings and structures. Where land is 10 feet or less above sea level, flooding may induce an extensive evacuation of residents for several miles inland. Hurricane Hugo, in 1989, was a category four hurricane at landfall. It made contact with land along the coast of South Carolina and into North Carolina, where it caused about seven billion dollars in damage.

Category Five: This is the most intense rating a hurricane can achieve. Winds speeds are greater than 155 mph with a storm surge of 18 feet or more above normal. Damage may include complete roof failure for some structures, some complete building failures, excessive damage to doors and windows, and mobile homes could be destroyed. Trees and shrubs would probably be blown down. Flooding may be expected three to five hours before the hurricane center passes, and may cause damage to lower floors of all structures that are located 15 feet or less above sea level and within 500 yards of the shoreline. There may be extensive evacuations for residents on low-lying ground within five to ten miles from the shoreline. An example of this type of hurricane was Hurricane Gilbert of 1988. This hurricane is the strongest one on record so far. Gilbert struck land at Cozumel, Mexico on September 14, 1988, causing extreme damage and loss of life.

This is the worst; winds blow at least 155 mph. It destroys buildings.

Basic Hurricane Safety Actions

Know if you live in an evacuation area. Know your home's vulnerability to storm surge, flooding and wind. Have a written plan based on this knowledge.

At the beginning of hurricane season (June 1st), check the supplies for your disaster supply kit, replace batteries and use food stocks on a rotating basis.

During hurricane season, monitor the tropics.

Monitor NOAA Weather Radio. It is an excellent / official source for real-time weather information and warnings.

If a storm threatens, heed the advice from local authorities. Evacuate if ordered.

Execute your family plan.

WATCH vs. WARNING - KNOW THE DIFFERENCE

A HURRICANE WATCH issued for your part of the coast indicates the possibility that you could experience hurricane conditions within 36 hours. This watch should trigger your family's disaster plan, and protective measures should be initiated, especially those actions that require extra time such as securing a boat, leaving a barrier island, etc.

A HURRICANE WARNING issued for your part of the coast indicates that sustained winds of at least 74 mph are expected within 24 hours or less. Once this warning has been issued, your family should be in the process of completing protective actions and deciding the safest location to be during the storm.

Caught in a Hurricane?

So, there's a hurricane heading your way? Well, have no fear. As long as you are properly prepared, you should have no worries.

If you are in an area that may be struck by a hurricane, there are certain measures you can take in anticipation of the storm. It is important to pay attention to weather reports because warnings may be issued. Weather forecasters and government weather services can also help you plan for what may happen during a storm. Safety is always first, of course!

Weather services will issue warnings and/or watches for certain areas that may be prone to hurricanes. Be sure to watch your local news stations, or listen to your radio for updates during storms.

If your area is designated as a storm watch area, especially a hurricane watch, take time to prepare for emergencies. Even though you may not be sure that a storm will hit your area, it is better to be safe than sorry. Preparing for a storm can involve several activities, such as storing food items, and bringing in loose objects, such as patio furniture or bicycles, from porches or lawns.

Some other tips:

Remember, tornadoes can be created from hurricanes. Be sure to keep a sharp look-out for them, just in case.

When the eye of the storm passes over your area, the weather may appear to be very calm, but DON'T LEAVE YOUR SHELTER. After the eye passes over your area, hurricane-force winds will once again reign. You don't want to be caught outside when they hit again.

Note: All images and most of content belongs to NASA website.