Hurricanes, typhoons and cyclones
Introduction
Hurricanes, cyclones and typhoons are terms used in different parts of the world to describe
a tropical cyclone. Tropical cyclones are known as:
• Hurricanes in the North Atlantic Ocean and north east Pacific Ocean
• Cyclones or tropical cyclones over the Indian Ocean
• Typhoons over the north west Pacific Ocean
• Cyclones or, occasionally, willy willies in Australia
All tropical cyclones are given names so that they can be identified and tracked as they
move. They mostly occur between 5º and 30º latitude north and south of the equator and
need plenty of warm, moist air from the sea to sustain themselves so they tend to die out
when they are over land.
Tropical cyclone wind strength is ranked in most parts of the world using the Saffir-Simpson
Hurricane Scale. This scale goes from a Category 1 storm with sustained winds of 74-95 miles
per hour, a storm surge of 4-5 feet and minimal damage to a Category 5 storm. This is the
most powerful type of storm with winds of more than 155mph, a storm surge of 18 feet or
more and consequent catastrophic damage including the destruction of buildings and
vegetation, major roads cut off and widespread flooding.
Damage caused by tropical cyclones
Hazards associated with tropical cyclones include:
• High winds: these can destroy buildings and damage trees, pylons and other
communications lines as well as to human life. Windows may be blown out.
• High seas: very large waves are a particular hazard to all forms of shipping including fishing
and leisure boats.
• Storm surges: the sea water levels rise significantly, often 20 feet over normal high tide
conditions, a very significant threat to life, buildings and infrastructure.
• Tornadoes: tornadoes may occur that add to a cyclone’s destructive power.
• Inland flooding: intense and prolonged rainfall can cause severe flooding which may occur
hundreds of miles from the coast.
Tropical cyclone seasons worldwide
There are seven tropical cyclone “basins” where storms occur on a regular basis. These
include:
Basin
Storm season
Area affected
Atlantic basin (including the
North Atlantic Ocean, the
Gulf of Mexico, and the
Caribbean Sea)
June 1st – November 30th
Mexico, Central America,
the
Caribbean
Islands,
Bermuda,
Macronesian
Islands & the Atlantic coast
of the USA. Occasionally
Venezuela & south eastern
Canada
Northeast Pacific basin (from
Mexico
to
about
the
international dateline)
May 15th–November 30th
Western Mexico, northern
Central America & Hawaii
Northwest
Pacific
basin
(from
the
international
dateline to Asia including
the South China Sea)
All year round with peak in
August & September and
lower activity in February &
March
China, Taiwan, Japan, South
Korea, Hong Kong, the
Philippines, Vietnam, and
Cambodia
North Indian basin (including
the Bay of Bengal and the
Arabian Sea)
April–December,
with
a
double peak in April & May
and October & November
Bangladesh, India, Sri Lanka,
Myanmar,
Thailand
and
Pakistan On rare occasions
Somalia and the Arabian
Peninsula
Southwest Indian basin (from
Africa to about 100E)
Late October–May with a
double peak in mid-January
& mid-February/early March.
Madagascar,
Mozambique,
South
Africa,
Kenya,
Reunion, Mauritius and the
Seychelles
Southeast Indian/Australian
basin (100E to 142E)
Late October–May with a
double peak in mid-January
& mid-February/early March.
Indonesia and Australia
Australian/Southwest Pacific
basin (142E to about 120W)
Late October–early May with
peak
activity
in
late
February/early March.
Australia, Papua New Guinea
and several Pacific Islands
Preparing for a tropical cyclone
If you live or work in an area prone to tropical cyclones or have responsibility for staff
members and volunteers who do, we recommend that you spend time preparing a written
emergency plan which takes into account all hazards associated with tropical cyclones (see
above) and that you include all your family members and/or work colleagues where
possible in your plan.
Before the tropical cyclone season:
 Know your home or office’s vulnerability to a storm surge, flooding and wind damage
and know your safest high ground and access route to it.
 If you do not live in an evacuation zone, designate a room with no windows or external
doors to act as your “safe room”.
 Prepare a disaster supply kit (see kit list below) and check the supplies in the kit at the
beginning of your tropical storm season. Replenish supplies as necessary.
Once a tropical cyclone warning has been issued:
 Keep up-to-date with the weather forecast and weather warnings and check your
neighbours are prepared.
 Use plywood or other material to protect all your windows.
 Secure or bring inside all garden furniture and outside objects which could pose a risk in
high winds. In addition, trim back or remove any trees or bushes that may pose a wind
hazard eg dead trees, overhanging branches, etc.
 Ensure your car’s fuel tank is full.
 Ensure you have some cash available.
 Set your fridge and freezer to their coldest setting so that your food will last longer
when/if your power supply is cut off.
 Follow the advice from the local authorities. Evacuate your home or office if you are
ordered to or go to your “Safe Room” if you are directed to do so and remain there until
you have been informed it is safe for you to leave it. Alternatively, move to a safe area
before access is cut off by high winds or floodwaters.
When a tropical cyclone strikes
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Follow your emergency plan
Turn off the gas, water and power supplies. Disconnect small electrical appliances.
Keep abreast of road conditions by listening in to the local media.
Beware the “eye” of the storm when the wind drops. Don’t assume the cyclone is over
as very strong winds will resume shortly from another direction.
 Recent research suggests that if you are in a high rise building when a tropical cyclone
arrives, you should stay below the 10th floor but still above any floors which may be at
risk of flooding.
 Keep away from windows as they can be blown out during a tropical cyclone. This poses
a significant risk to occupants in a building as well as those in areas around high rise
buildings.
After the tropical cyclone has ended
 Continue to listen to the radio for further information and follow the advice of the local
authorities.
 Remain alert to the risk of floodwaters and heavy rainfall after the cyclone has left your
area. Do not attempt to cross flowing water. You may lose control of your car in as little
as 6 inches of water.
 Don’t try to access a building which is surrounded by water and don’t allow children to
play near flooded areas.
 Do not eat fresh food that has been in contact with floodwaters. Wash tins of food with
soap and water if they have been in contact with floodwaters. Check refrigerated and
frozen food. Discard it if it is spoilt.
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Stay away from power lines which are loose or dangling. Report them to the local
power company.
Inspect your home and/or business for damage. Take photos of the damage and
contact your insurance company, Wear protective clothing and be cautious so avoid
injury.
Take care of pets and ensure you have them under your control.
Avoid using candles in the dark if at all possible. Use a torch instead.
Be aware that the risk of water-borne diseases increases during flooding.
Use the telephone for emergency calls only.
Contact your family, employer and Embassy/High Commission to let them know you
are safe. You can do this via the Red Cross if direct contact is not possible.
Sources
The National Hurricane Center (USA), Australian Government Bureau of Meteorology, the
Met Office, Atlantic Oceanographic & Meteorological Laboratory, American Red Cross.
Disaster supply kit (adapted from lists published by the National Hurricane
Center (USA) and the American Red Cross)
Kit contents should include:
 Water - at least 1 gallon (4 litres) daily per person for 3 to 7 days.
 Food - at least enough for 3 to 7 days.
— non-perishable packaged or canned food / juices
— foods for infants or the elderly
— snack foods
— non-electric can opener
— cooking tools / fuel
— paper plates / plastic utensils
 Blankets/pillows, etc.
 Clothing - seasonal / rain gear/ sturdy shoes
 First Aid Kit/medicines/prescription medicines
 Insect repellent & suncream
 Special items - for babies and the elderly
 Toiletries/hygiene items/moisture wipes
 Torch/batteries
 Radio (battery operated)
 Telephones - Fully charged mobile phone with extra battery and a traditional (not
cordless) telephone set
 Cash (with some small bills) and credit cards - banks and ATMs may not be available for
extended periods
 Camera – useful for taking photos of any damage
 Keys (extra sets for the house & car)
 Toys, books and games
 Important documents - in a waterproof container or watertight resealable plastic bag
— passports, insurance, medical records, bank account numbers, Social Security card,
National Insurance number, etc.
 Family & emergency contact information
 Tools - keep a set with you during the storm. Include a multi-purpose tool.
 Vehicle fuel tanks filled
 Map(s) of the area
 Pet care items
— proper identification/immunisation records/medications
— ample supply of food and water
— a carrier or cage
— muzzle and leash
InterHealth Authors
Cathy Travis
Last updated: February 2013