TYPHOON, CYCLONE, HURRICANE

By: Marloid T. Garcia, Desiree Narral, Eisthine Nichole Oco

A Typhoon is a mature tropical

cyclone that develops in the

western part of the North

Pacific Ocean between 180°

and 100°E. This region is

referred to as the northwest

Pacific basin.

The term typhoon is used only in the northwestern

part of the Pacific Ocean. In the northeastern

part of the Pacific Ocean and in the northern

part of the Atlantic Ocean, the equivalent term is

hurricane. Thus, a hurricane on one side of the

Pacific Ocean will be called a typhoon if it

crosses into the other side.

In the Philippines, we use the same word for all

categories of tropical cyclones. We call it bagyo

whether it is a tropical depression, a tropical storm

or a typhoon.

The origin of the name "typhoon"

The origin of the name "typhoon"

The formation of typhoonTyphoons start

off as tropical

thunderstorms.

The strong

winds pull in

moisture from

the oceans.

The formation of typhoonThe thunderstorms

convert the

moisture into heat.

The heat causes

more air to flow to

the centre of the

storm causing

evaporation.

The formation of typhoon

All the heat

and air flow

toward the

eye creating

the typhoon.

What conditions favor the formation of typhoons?

There are six requirements for the formation of a typhoon: sufficiently warm sea surface temperatures, atmospheric instability, high humidity in the lower to middle levels of the troposphere, enough Coriolis force to develop a low pressure center, a pre-existing low level focus or disturbance low vertical wind shear.

A supertyphoon as seen from

high above the Earth; at the

center is the “eye” of the

supertyphoon. Image by NASA

Earth Observatory

The picture shows a supertyphoon as

viewed from up above the Earth. A

typhoon looks the same, only smaller.

See the clouds in a spiral arrangement?

They are being blown by winds in a

counter-clockwise direction. In a

supertyphoon, the wind speed is

greater than 200 kilometers per hour

(kph).

If the wind speed is less, from 119 to 200

kph, then it is called a typhoon. If the

wind speed is between 65 and 118 kph,

it is called a tropical storm. And when

the wind speed is between 35 to 64

kph, it is a tropical depression.

Tropical depression, tropical storm, typhoon, and

supertyphoon are categories of tropical cyclones. In

simple terms, a tropical cyclone is a system of

thunderstorms that are moving around a center. As

the winds intensify or weaken, the category is

upgraded or downgraded accordingly.

Category Maximum Wind Speed

kilometers per hour (kph)

Tropical Depression 64

Tropical Storm 118

Typhoon 200

Super typhoon Greater than 200

Strong wind

Foehn

Salty Wind

Waves

Storm surge

Torrential rain

Flood

Landslide

Debris flows

Disease and

pests

Epidemic

diseases

The damage caused from a typhoon, on

the other hand, is many. These will be

discussed briefly as follows:

Since the middle of the 20th Century, American forecasters have named

tropical storms after people, originally using only female names.

Philippine forecasters from the now-PAGASA started assigning Filipino

names to storms in 1963 following the American practice, using names of

people in alphabetical order, from A to Z.[9] Beginning in January 2000,

the World Meteorological Organization"s Typhoon Committee began

assigning names to storms nominated by the 14 Asian countries who are

members with each country getting 2 to 3 a year. These names, unlike

the American and Filipino traditions, are not names for people

exclusively but include flowers, animals, food, etc. and they are not in

alphabetical order by name but rather in alphabetical order by the

country that nominated the name. After January 2000, Filipino

forecasters continued their tradition of naming storms that enter the

Philippines Area of Responsibility and so there are often two names for

each storm, the PAGASA name and the so-called "international name".

Names of storms

PUBLIC STORM WARNING SIGNALS (PSWS)

PSWS #

What it means The following may happen What to do

1

A tropical cyclone will affect the localityWinds of 30-60 kph

may be expected in at least 36 hours or

irregular rains may be expected within 36

hours

Twigs and branches of small trees are brokenSome banana plants are tilted or downed

Some houses of very light materials partially unroofed

Rice crops suffer significant damage in its flowering stage

Watch out for big wavesListen to severe weather bulletin

issued by PAGASA

2

A tropical cyclone will affect the locality

Winds of greater than 60 kph up to 100 kphmay be expected in

at least 24 hours

Large number of nipa and cogon houses may be partially or totally unroofed

Some old galvanized iron roof may be peeled off

Winds may bring light to moderate damage to exposed communities

Some coconut trees may be tilted while few are broken

Few big trees may be uprootedMany banana plants may be downed

Rice and corn may be adversely affected

Avoid riding in small seacraftThose who travel by sea and air should avoid unnecessary risksPostpone outdoor activities of

children

3

A tropical cyclone

will affect locality

Winds of greater

than 100 kph to 185

kph may be

expected in at

least 18 hours

Many coconut trees broken or destroyed

Almost all banana plants downed and a large

number of trees uprooted

Rice and corn crops suffer heavy losses

Majority of all nipa and cogon houses uprooted or

destroyed; considerable damage to structures of

light to medium construction

Widespread disruption of electrical power and

communication services

Moderate to heavy damage experienced in

agricultural and industrial sectors

Avoid riding in any

seacraft

Seek shelter in strong

buildings

Evacuate from low-

lying areas

Stay away from coasts

and river banks

4

A very intense

typhoon will affect

locality

very strong winds of

more than 185 kph

maybe expected

in at least 12 hours

Coconut plantation may suffer extensive damage

Many large trees maybe uprooted

Rice and corn plantation may suffer severe losses

Most residential and institutional buildings of mixed

construction maybe severely damaged

Electrical power distribution and communication

services maybe severely disrupted

Damage to affected communities can be very

heavy

all travels and outdoor

activities should be

cancelled

Evacuation to safer

shelters should have

been completed by

now

The locality is very

likely to be hit directly

by the eye of the

typhoon.

The Philippines is prone to typhoons and other natural

disasters because it lies astride the typhoon belt, in the

active volcanic region known as the "Pacific Ring of

Fire," and in the geologically unstable region between

the Pacific and Eurasian tectonic plates. It is a country

surrounded by moist air, so the typhoon is able to feed

on that. The typhoon also needs cold air. Once these

are together, the air spins in circles. The typhoon is then

formed. All the things that a typhoon needs are

provided in and around the Philippines, resulting in

several typhoons a year.

Why is the Philippines prone to typhoons ?

A Cyclone is an area of closed, circular fluid

motion rotating in the same direction as the

Earth. This is usually characterized by inwardspiraling winds that rotate anti-clockwise in the

Northern Hemisphere and clockwise in theSouthern Hemisphere of the Earth. Most large-scale cyclonic circulations are centered on

areas of low atmospheric pressure. Cyclonesare also referred to as hurricanes and typhoons.They consist of the eye, eyewall and rainbands.

A hurricane is a type of tropical

cyclone or severe tropical storm that

forms in the southern Atlantic Ocean,

Caribbean Sea, Gulf of Mexico, and in

the eastern Pacific Ocean. A typical

cyclone is accompanied by

thunderstorms, and in the Northern

Hemisphere, a counterclockwise

circulation of winds near the earth’s

surface.

What is the

difference

between a

hurricane, a

cyclone, and

a typhoon?

Hurricanes, cyclones, and typhoons are all the same weather

phenomenon; we just use different names for these storms in different

places. In the Atlantic and Northeast Pacific, the term “hurricane” is

used. The same type of disturbance in the Northwest Pacific is called a

“typhoon” and “cyclones” occur in the South Pacific and Indian

Ocean.

The ingredients for these storms include a pre-existing weather

disturbance, warm tropical oceans, moisture, and relatively light winds.

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.

In the Atlantic, hurricane season officially runs June 1 to November 30.

However, while 97 percent of tropical activity occurs during this time

period, there is nothing magical in these dates, and hurricanes have

occurred outside of these six months.