Hurricane Season begins June 1st and continues
through November 30th. Practice Hurricane Preparedness and learn about
Hurricane Survival.
Evacuation Routes
The following maps will be able to help you plan your evacuation:
Weather Terminology
- Gale Warning: Wind speed of 39-64 miles per hour expected.
- Tropical Disturbance: A moving area of thunderstorms in the tropics.
- Tropical Wave:
A westward-moving, low-pressure trough in the deep easterly current
that tends to organize low-level circulation. It sometimes travels
thousands of miles with little change in shape, producing showers and
thunderstorms along its path.
- Tropical Depression: An area of low pressure, rotary circulation of clouds and winds up to 38 miles per hour.
- Tropical Storm:
Counterclockwise circulation of clouds and winds (develops over warm
tropical waters) with windspeeds ranging from 39-73 miles per hour. At
this stage, the storm is assigned a name.
- Hurricane: A tropical storm with windspeeds of 74 miles per hour or more, and dangerously high water and waves.
- Hurricane "Eye":
The relatively calm area near the center of the storm where winds are
light, and the sky often is partly cloudy. The calm area is deceptive
because it is bordered by maximum-force winds and torrential rains; it
can last from several minutes to more than an hour.
- Storm Surge:
An abnormal rise in sea level produced by the strong winds and low
pressure within a hurricane. The storm surge occurs in the right half
of the storm as it makes landfall. The storm surge potentially could
elevate sea level from 2-20 feet. (Nine out of 10 hurricane-related
deaths occur as a result of storm surge rather than winds.) For more
information about storm surge, visit
- Advisory: Hurricane and storm information delivered to the public every six hours.
- Intermediate Advisory: Hurricane and storm information updated every 2-3 hours, or as necessary.
- Special Advisory: Hurricane and storm information delivered when there is a significant change in storm-related weather conditions or warnings.
- Gale Warning: An advisory that 39-54 mph sustained winds and strong wave action are expected.
- Storm Warning: An advisory that 55-73 mph sustained winds and strong wave action are expected.
- Hurricane Watch: An announcement of possible hurricane conditions, for a particular area, within 36 hours.
- Hurricane Warning: A advisory that a hurricane is expected to strike a specified area within 24 hours or less.
- Hurricane Eye:
The relatively calm area in the center of the storm where winds are
light, and the sky often is partly cloudy. The calm area is deceptive
because it is bordered by maximum-force winds and torrential rains.
Hurricane Danger Zone
The coordinates of a hurricane given by the weather
service identify the location of the storm's "eye". The average
storm is 250 miles in diameter: thus the danger zone extends some
100 miles on either side of the coordinates.
If a storm is projected to hit our area, maximum conditions
would exist if the storm eye crossed over us, or to the immediate
south. Lessor conditions would be expected if the storm eye crossed
to the north of our area.
Breakers coming ashore in a hurricane travel at about
one-half the speed of winds in the storm. Relating this to pressure
created by the breakers, that means an impact of 10,000 pounds of
pressure per square foot.
Hurricane Intensity
The National Weather Service categorizes hurricanes by intensity on
a scale of 1 to 5, as follows:
|
CATEGORY
I
II
III
IV
V |
WIND SPEED
74- 95 mph
96-110 mph
111-130 mph
131-155 mph
155+ mph |
STORM SURGE
4- 5 ft.
6- 8 ft.
9-12 ft.
13-18 ft.
18+ ft. |
Severity Of Damage
The amount of damage that you can expect from a hurricane is
directly linked to the wind velocity of the storm. Winds in an intense
storm can reach a sustained velocity of more than 150 miles per hour,
with gusts up to 200 miles per hour.
The National Hurricane Center
uses the Saffir-Simpson scale to classify (1-5 rating) hurricanes based
on present intensity. Here is a summary of possible damage to
shorelines, structures, and vessels in each case.
Category 1
Windspeed: 74-95 mph
Storm Surge: 4-5 feet above normal
Effects: No real damage to building structures. Damage primarily to
unanchored mobile homes, shrubs, and trees. Some damage to poorly
constructed signs. Flooded low-lying coastal roads, minor pier damage,
some small craft in exposed anchorages torn from moorings.
Category 2
Windspeed: 96-110 mph
Storm Surge: 6-8 feet above normal
Effects: Some damage to roofing material, doors, and windows of
buildings. Considerable damage to shrubs and trees -- some trees blown
over. Considerable damage to mobile homes, poorly constructed signs,
and piers. Coastal and low-lying roads leading inland are flooded 2-4
hours before the hurricane eye passes over the area. Marinas are
flooded and small craft in unprotected anchorages torn from moorings. Hurricane Bertha was a category 2 at landfall.
Category 3
Windspeed: 111-130 mph
Storm Surge: 9-12 feet above normal
Effects: Some structural damage to small houses and utility buildings
with a minor amount of curtainwall failures. On coast, smaller
structures are destroyed by coastal flooding; larger structures are
destroyed by battering of waves and floating debris. Trees and shrubs
damaged; foliage blown off trees. Mobile homes and poorly-constructed
signs are destroyed. Low-lying roads leading inland flooded 3-5 hours
before the eye passes over the area. Evacuation of low-lying residences
within several blocks of the shoreline might be necessary. Terrain
(continuously) lower than 5 feet above sea level might be flooded
inland 8 miles or more. Hurricane Fran was a category 3 at landfall.
Category 4
Windspeed: 131-155 mph
Storm Surge: 13-18 feet above normal
Inland Flooding: Up to 10 feet above sea level, as far as 6 miles inland.
Effects: More extensive failure of curtainwalls; complete failure of
roof structures on some small houses. Extensive damage to doors and
windows of all structures. Major flooding and wave battering damage to
lower floors of structures near shore. All signs, shrubs, and trees are
blown down. Mobile homes are completely destroyed. Low-lying roads
leading inland flooded 3-5 hours befre the eye passes over the area.
Major beach erosion. Terrain lower than 10 feet above sea level might
be flooded. Evacuation required for residential areas as far inland as
6 miles. Hurricane Hugo was a category 4 hurricane at landfall.
Category 5
Windspeed: 155+ mph
Storm Surge: 18+ feet above normal
Inland Flooding: Up to __ feet above sea level, as far as __ miles inland.
Effects: Complete failure to roofs of many residential and industrial
buildings. Complete failure to some buildings; small utility buildings
blown over or blown away. Mobile homes completely destroyed. Severe and
extensive damage to windows and doors of all structures. Major damage
to lower floors of all structures located less than 15 feet above sea
level, within 500 yards of the shore. Evacuation required for
residential areas on low ground within 5-10 miles of shoreline.
Future Hurricane Names
2006 names will be posted when available.
For more information about hurricanes, visit The National Weather Service's Hurricane Center.