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Cuba > Huracan-Hurricanes-Cyclones |
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Hurricane Breifing |
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Facts
What are hurricanes?
Hurricanes are cyclones of tropical origin with wind speeds of at least 74 miles per hour. In other words, a hurricane is large, rotating storm winds that moves around a relatively calm center called the 'eye'. These storms are known as 'typhoons' in the western Pacific and 'cyclones' in the Indian Ocean. Each storm usually has a life span of several days.
When is hurricane season?
The hurricane season begins June 1st and runs through November 30th , with a maximum number of storms occurring in August and September. Hurricanes have been reported in January and December. A storm becomes a tropical storm and receives a name, when its winds reach 39 mph. It becomes a hurricane when winds hit 74 mph.
What's the eye of a hurricane?
The eye of the hurricane is the innermost portion of the storm. This zone is surprisingly calm with little or no wind. Within the eye, the skies are often clear, despite the fact that winds and clouds continue to rage around the edge of the eye.
• The eye is not always in the center of the storm. Sometimes it turns or moves in various directions with the storm itself, which continues to move forward on its own course.
The phases of a hurricane’s life
Although there are several different opinions when it comes to the definition of the various phases of a hurricane's life. Most authorities seems to agree there are four basic stages:
• 1. The formative state
• 2. The immature stage
• 3. Maturity
• 4. The decay and dying stage
How long do hurricanes last?
The life span of hurricanes averages 10 days, although some last much longer.
Hurricanes usually move over a large region during their life span, therefore, the average hurricane normally affects a given area for only a day or two.
How are hurricanes named?
Forecasters began naming hurricanes in order to provide ease of communication between them and the general public in areas regarding forecasts, watches and warnings. By naming hurricanes, there is a reduction in confusion about what storm is being described.
• Prior to 1950, hurricanes were assigned names by the year in which they occurred plus a letter from the alphabet (i.e. 1942A, 1942 B, etc.). It then became the trend to give hurricanes human names. Experience shows that the use of girls' and boys' names in written and spoken communication is shorter, quicker, and causes fewer mistakes than any other hurricane identification used to date.
• Each season a potential list of names is prepared for the up coming hurricane season. The list contains a name for each letter of the alphabet. (The letters Q, U, X, Y, Z are not included because there are not many names beginning with those letters.) These lists are recycled every six years and names are replaced when a hurricane name is retired.
Categories
Category 1: Minimal damage
Winds of 74-95 mph and storm surges of 4-5 ft. No significant wind damage to well constructed buildings. Some damage is done to poorly constructed signs. Wind damage primarily occurs to mobile homes, shrubbery, trees, and foliage. Low lying roads are inundated by storm surge. Minor pier damage occurs.
Example: Danny, 1997
Category 2: Moderate damage
Winds of 96-110 mph and storm surges of 6-8 ft. Some roofing material, doors, windows of homes and businesses are damaged by winds. Considerable wind damage done to mobile homes and vegetation. Low lying roads are inundated by storm surge. Considerable damage done by storm surge and wave action to piers. Small craft in unprotected anchorages break their moorings.
Example: Flossy, 1956
Category 3: Extensive damage
Winds of 111-130 mph and storm surges of 9-12 ft. Winds cause structural damage to homes and utility buildings with a minor amount of curtainwall failure. Mobile homes are destroyed. Storm surge flooding destroys many smaller buildings while large buildings are damaged by floating debris. Terrain continuously lower than 10 feet above mean sea level is flooded.
Example: Andrew, 1992
Category 4: Extreme damage
Winds of 131-155 mph and storm surges of 13-18 ft. More extensive curtainwall failures with some complete roof failure on homes. Major damage to lower floors of homes and businesses from storm surge flooding. Terrain continuously lower than 15 feet above mean sea level is flooded.
Example: Audrey, 1957
Category 5: Catastrophic damage
Winds greater than 155 mph and storm surges greater than 18 ft. Compete roof failure of many homes and businesses. Complete structural failure of many small buildings. Major storm surge flooding to areas lower than 20 feet above mean sea level.
Example: Camille, 1969
Preparations
Hurricane watches and warnings
A hurricane watch is issued when hurricane conditions are possible within 24 to 36 hours. A hurricane warning is issued when hurricane conditions (winds of 74 miles per hour or greater, or dangerously high water and rough seas) are expected in 24 hours or less.
What to do in a hurricane watch
• Listen to a battery-operated radio or television for hurricane progress reports. Check emergency supplies. Fill your car with gas. Bring in outdoor objects such as lawn furniture, toys, and garden tools and anchor objects that cannot be brought inside.
• Secure buildings by closing and boarding up windows. Remove outside antennas.
• Turn refrigerator and freezer to coldest settings. Open only when absolutely necessary and close quickly.
• Store drinking water in clean bathtubs, jugs, bottles, and cooking utensils.
• Review evacuation plan.
• Moor your boat securely or move it to a designated safe place. Use rope or chain to secure boat to trailer. Use tiedowns to anchor trailer to the ground or house.
• During a hurricane warning listen constantly to a battery-operated radio or television for official instructions.
• If in a mobile home, check tiedowns and evacuate immediately.
• Store valuables and personal papers in a waterproof container on the highest level of your home.
• Avoid elevators. If at home, stay inside, away from windows, skylights, and glass doors.
• Keep a supply of flashlights and extra batteries handy. Avoid open flames, such as candles and kerosene lamps, as a source of light.
• If power is lost, turn off major appliances to reduce power 'surge' when electricity is restored.
If ordered to evacuate
• Leave as soon as possible. Avoid flooded roads and watch for washed-out bridges.
• Secure your home by unplugging appliances and turning off electricity and the main water valve.
• Tell someone outside of the storm area where you are going. If time permits, and you live in an identified surge zone, elevate furniture to protect it from flooding or better yet, move it to a higher floor.
• Bring pre-assembled emergency supplies and warm protective clothing. Take blankets and sleeping bags to shelter. Lock up home and leave.
Preparation and safety tips
• Much of the USA population lives within striking distance of a hurricane. It is important for people who live in these areas to have preparation plans well before a hurricane threatens. Here are some tips that you can use to design and implement a hurricane preparation plan.
• Plan an evacuation route.
• Contact the local emergency management office or American Red Cross chapter, and ask for the community hurricane preparedness plan. This plan should include information on the safest evacuation routes and nearby shelters. Learn safe routes inland. Be ready to drive 20 to 50 miles inland to locate a safe place. Have disaster supplies on hand:
• Flashlight and extra batteries, Portable, battery-operated radio and extra batteries, First aid kit and manual, Emergency food and water, Non-electric can opener, Essential medicines, Cash and credit cards, Sturdy shoes
Preparing buildings and grounds
• Remove fragile objects from wall shelves. Store them in closets to safeguard them from the storm's vibrations. Check and close all faucets. Unplug all electrical appliances from wall outlets. Disconnect television antennas from the sets. Close and lock all windows. Draw blinds, shades, and draperies.
• Place folded towels on the window sills to absorb leaking water. Wedge patio doors so they cannot be torn off. Remove outdoor furniture, container plants and decorative objects from patios, terraces, verandas, and porches. Store them inside so they will not become flying missiles. Test the generator regularly, so it will be available for emergencies. Check all equipment for readiness: fire extinguishers, first aid kits, tools, etc. Install shutters (commercial type, plywood or masonite). Check fasteners to make sure they fit snugly against the wall.
Statistics
Cyclones*
Average yearly Atlantic cyclones
Last 110 Year Average (1886-1995) 8.5
Last 50 Year Average (1946-1995) 9.7
Last 10 Year Average (1986-1995) 9.8
Most cyclones in one year
1. 21 in 1933
2. 19 in 1995
3. 18 in 1969
Compare this to the NW Pacific Basin where the lowest number ever recorded in one year was a paltry 19.
Most cyclones in one year
1. 21 in 1933
2. 19 in 1995
3. 18 in 1969
Compare this to the NW Pacific Basin where the lowest number ever recorded in one year was a paltry 19.
Has there been a year with no cyclones?
No, there has never been a season with no tropical cyclones. However, there was only one in 1914 and one in 1890.
Largest tropical cyclone
Typhoon Tip (NW Pacific, October, 1979) - 870mb with sustained sfc wind 165 kt.
Longest tropical cyclone
Hurricane/typhoon John (August-September 1994) lasted 31 days.
Longest Atlantic tropical cyclone
Hurricane Ginger (1971) lasted 28 days.
*Cyclones refer to tropical storms or hurricanes
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