Hurricane Facts

 

THE FOLLOWING INFORMATION, PHOTOS AND GRAPHS ARE PROVIDED BY THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, "HURRICANE BASICS FOR EVERYONE". VISIT THEIR SITE,WWW.NHC.NOAA.GOV FOR THE LATEST HURRICANE INFORMATION.

TERMS AND DEFINITIONS 
WHAT IS A HURRICANE?

A “hurricane” is the most severe category of the meteorological phenomenon known as the “tropical cyclone.” A tropical cyclone 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 (OR LESS).

Tropical Storm
An organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds of 39-73 mph.

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

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.

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.

Hurricane Hazards  
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The main hazards associated with tropical cyclones and especially hurricanes are storm surge, high winds, heavy rain and flooding, as well as tornadoes. The intensity of a hurricane is an indicator of damage potential. Impact, however, is a function of where and when the storm strikes. Hurricane Diane (1955) hit the northeastern U.S. and caused 184 deaths. It was only a Category 1 hurricane, but the 13th deadliest since 1900. Hurricane Agnes (1972), also a Category 1 hurricane, ranks fifth, with damages estimated at $6.9 billion when adjusted for inflation.1

A storm surge is a large dome of water, 50 to 100 miles wide, that sweeps across the coastline near where a hurricane makes landfall. It can be more than 15 feet deep at its peak. The surge of high water topped by waves is devastating. Along the coast, storm surge is the greatest threat to life and property.

Hurricane winds not only damage structures, but the barrage of debris they carry is quite dangerous to anyone unfortunate enough (or unwise enough!) to be caught out in them.Damaging winds begin well before the hurricane eye makes landfall. Tropical cyclones frequently produce huge amounts of rain, and flooding can be a significant problem, particularly for inland communities.

A typical hurricane brings at least 6 to 12 inches of rainfall to the area it crosses. The resulting floods may cause considerable damage and loss of life, especially in areas where heavy rains mean flash floods. Tornadoes spawned by landfalling hurricanes can cause enormous destruction. As a hurricane moves shoreward, tornadoes often develop on the fringes of the storm. 

These hazards can bring other consequences not directly related to the storm. For example, hurricane-related deaths and injuries are often the result of fires started by candles used when the electricity fails. Heart attacks and accidents frequently occur during the clean-up phase. And depending on the industrial facilities in your area, hurricane damage might cause chemical spills that could make the disaster even worse.

1 Hurricanes: Their Nature and Impact on Society, (Pielke and Pielke, 1997, p. 125)

Saffir-Simpson Hurricane Scale
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Category

Winds

Effects

One

74-95 mph

No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal road flooding and minor pier damage.

Two

96-110 mph

Some roofing material, door and window damage to buildings. Considerable damage to vegetation, mobile homes and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of center. Small craft in unprotected anchorages break moorings.

Three

111-130 mph

Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet at sea level may be flooded inland eight miles or more.

Four

131-155 mph

More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of beach. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet at sea level may be flooded, requiring massive evacuation of residential areas inland as far as six miles.

Five

Greater than 155 mph

Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet at sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within five to 10 miles of the shoreline may be required.

 ACTION CHECKLIST FOR YOUR HOME AND FAMILY
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Here is a list of the many things to consider before, during and after a hurricane. Some of the safety rules will make things easier for you during a hurricane. All are important and could help save your life and the lives of others.

In general:

·         If you live on the coastline or offshore islands, plan to leave your home

·         If you live near a river or in a flood plain, plan to leave your home

·         If you live on high ground, away from coastal beaches, consider staying. In any case, the ultimate decision to stay or leave will be yours.

·         At beginning of Hurricane Season (June), make plans for action

·         Learn the storm surge history and elevation of your area

·         Learn safe routes inland

·         Learn location of official shelters

·         Determine where to move your boat in an emergency

·         Trim back dead wood from trees

·         Check for loose rain gutters and down spouts

·         If shutters do not protect windows, stock boards to cover glass
 

When a Hurricane Watch is Issued for Your Area:

·         Check often for official bulletins on radio, TV, or NOAA Weather Radio

·         Fuel car

·         Check mobile home tie-downs

·         Moor small craft or move to safe shelter

·         Stock up on canned provisions

·         Check supplies of special medicines and drugs

·         Check batteries for radio and flashlights

·         Secure lawn furniture and other loose material outdoors

·         Tape, board, or shutter windows to prevent shattering

·         Wedge sliding glass doors to prevent their lifting from their tracks 
 

When a Hurricane Warning is Issued for Your Area:

·         Stayed tuned to radio, TV, or NOAA Weather Radio for official bulletins

·         Stay home if sturdy and on high ground, board up garage and porch doors

·         Move valuables to upper floors

·         Bring in pets

·         Fill containers (bathtub) with several days supply of drinking water

·         Turn up refrigerator to maximum cold and don’t open unless necessary

·         Use phone only for emergencies

·         Stay indoors on the downwind side of house away from windows

·         Beware of the eye of the hurricane

·         Leave mobile homes

·         Leave areas that might be affected by storm tide or stream flooding (listen for evacuation recommendations/orders)

·         Leave early in daylight if possible

·         Shut off water and electricity at main stations

·         Take small valuables and papers, but travel light

·         Make plans to ensure the safety of pets

·         Lock up your house

·         Drive carefully to the nearest designated shelter using recommended evacuation routes
 

After the All-Clear is Given:

·         Drive carefully, watch for dangling electrical wires, undermined roads and flooded low spots

·         Don’t sight-see

·         Report broken or damaged water, sewer and electrical lines

·         Use caution when re-entering your home

·         Check for gas leaks

·         Check food and water for spoilage

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