Typhoons form in the western Pacific Ocean and impact the Philippines frequently between July and November. They are categorized based on wind speed from tropical depression to violent typhoon. Typhoons cause widespread damage through strong winds, heavy rain, and storm surge. They destroy buildings, crops, and vegetation. Loss of life is also common. The economic impacts include damage to infrastructure and negative effects on stock markets. Mitigation efforts include early warning systems, evacuation plans, and policies around suspending activities when typhoons hit.

1. TYPHOON
Causes and mechanisms,
impacts and effects, and
Mitigation

2. What is Typhoon?
• Tropical Cyclones that develops in the north-
western part of the Pacific
Ocean between 180° and 100°E.
• In the Philippines, tropical cyclones (typhoons) are
called bagyo. The term bagyo, a Filipino word
meaning typhoon arose after a 1911 storm in the
city of Baguio had a record rainfall of 46 inches
within a 24-hour period..

3. Typhoons are categorized into five:
• Category 1 - Tropical Depression
-sustains winds between 119 and 153 km/hour (km/h).
It is the first notable stage in the formation of a
hurricane.(Morakot)
• Category 2 - Tropical Storm (TS)
- has winds between 154 and 177 km/h.
-a tropical storm is a system of intense thunderstorms
that progressively intensifies.
• Category 3 - Strong Typhoon
-A strong typhoon is a system of low pressure and
intense winds (between 178 and 209 km/h).(Maemi-South
Korea)

4. • Category 4 - Intense Typhoon (or Hurricane)
-An intense typhoon sustains high winds of 210
to 249 km/h and is classified as a category-5 storm,
which carries the highest element of risk.
• Category 5 - Violent Typhoon
-A violent typhoon is characterized by winds
exceeding 249 km/h.

5. • Variability in Activity
On an annual time scale, activity reaches
a minimum in February, before increasing
steadily through June, and spiking from
July through October, with September
being the most active month for tropical
cyclones in the Philippines. Activity falls
off significantly in November.

6. List of Philippine Typhoon
(1970-2011)
Name Period of
occurrence
Deaths Damage
(in billion)
Highest wind
speed in kph
Areas most
affected
Sening
(Joan)
October
11-15,1970
768 10.7 280 Bicol
region,calabarzon
Herming
(betty)
August o7-
14, 1987
94 39.9 260 Samar, Bicol
Region
Ruping
(Mike)
November
10-14,
1990
748 18.2 285 Cebu C
Harurot
(Imbudo)
July 13-
24,2003
64 3.87 240 Cagayan
Valley,CARIlocos
region
Unding
(Muifa)
November
14-26,2004
69 3.87 240 Bicol Region,
MIMAROPA

7. • Milenyo (Xangsane)-2006
• Frank (Fengshen) – 2008
• Ondoy (Ketsana) – 2009
• Bebeng (Aere) – 2011
• Ambo (Mawar) – 2012

8. These are the ff. typhoons hits in the Philippines
(2012)
• AMBO
• BUTCHOY
• COSME
• DINDO
• ENTENG
• FRANK
• GENER
• HELEN
• IGME
• SIONY
• TONYO
• YOYONG
• ZOSIMO
• JULIAN
• KAREN
• LAWIN
• MARCE
• NINA
• OFEL
• PABLO
• QUINTA
• ROLLY
• ULYSSES
• VICKY
• WARREN

9. CAUSES OF TYPHOON
TRANSFORMATION
Pre-conditions and Conditions
of Typhoons

10. PRE-CONDITIONS OF
TYPHOON FORMATION
MONSOON TROUGH
This is an extension of the
Inter- Tropical
Convergence Zone where
cyclonic spin has
developed. The ITCZ is a
trough is a low pressure
created by the
convergence of the
northeast and southeast
trade winds.

11. TROPICAL UPPER
TROPOSPHERIC
TROUGH
The typical low
pressure center that
forms a typhoon
starts at the lower
levels and is warm
compared to its
environment.

12. FRONT
Stall over tropical
water.
A front has a cyclonic
spin associated with
it. If winds aloft
become favorable
with little wind shear,
showers and storms
could become more
numerous and cause a
typhoon to form.

13. MESOSCALE
CONVECTIVE
SYSTEM
These organized
clusters of storms can
move off a continental
landmass and drift
over warm waters. If
they already contain a
small vortex in the
cluster, this may make
to region even more
favorable for tropical
cyclone development.

14. 7 BASINS WHERE TROPICAL CYCLONE DEVELOPS
• NORTH ATLANTIC OCEAN
June 1- November 30. The
most active period runs
from about mid August
through the latter part of
October.
( Caribbean, Bermuda, Central
America etc.)
• EASTERN NORTH PACIFIC
OCEAN
May 15 - November 30.
This is the second most
active region for tropical
cyclones in the world.
These storms mostly move
into the open eastern
Pacific Ocean but can
affect western Mexico and
sometimes after
developing, Hawaii.

15. • ARABIAN SEA ( Severe
Cyclonic Storm)
April 1 - December 30. This
basin has a double
maximum because of the
monsoon trough moving
through at two different
times of the year.
• SOUTHWEST PACIFIC
OCEAN (STC)
October 15 - May 1. These
tropical cyclones may affect
eastern Australia.
• NORTHWEST PACIFIC
OCEAN(Typhoon)
All year. This is the most
active basin in the world.
Most typhoons form
between July through
November. The tropical
cyclones that form here
can affect the Philippines,
Southeast Asia including
China and Taiwan, and
Japan.

16. • SOUTHEAST INDEAN
OCEAN ( STC)
October 15 - May. These
tropical cyclones may affect
northern and western
Australia. This basin has a
double maximum in mid
January, and mid February
through early March.
• SOUTHWEST INDIAN
OCEAN ( TC)
October 15 - May 15.
These tropical cyclones
may affect Madagascar and
south-eastern Africa. A
double maximum occurs in
mid January and mid
February through early
March.

17. THE LIFE OF A TYPHOON
THE FOUR STAGES OF THE LIFE OF A
TYPHOON

18. •FORMATIVE STAGE
•IMMATURE STAGE
•MATURE STAGE
•DECAYING STAGE

20. EFFECTS OF TYPHOON

21. BUILDINGS AND INFRASTRUCTURE
The two most destructive forces
associated with typhoons are
wind and rain. According to the
Green Fun website, typhoon
winds can affect buildings and
other structures in two ways:
through direct force and through
projectiles. The heavy and
persistent rainfall that typhoons
bring can also have devastating
effects. In addition to making
homes uninhabitable, the flooding
associated with typhoons can
make roads impassable, which can
cripple rescue and aid efforts.

22. TREES AND VEGETATION

23. WATERCRAFT AND WATER OPERATIONS

24. L
I
F
E

25. ECONOMICAL EFFECTS
• Different countries experience different types of natural
calamities. US are known for experiencing devastating
hurricanes while Japan is prone to earthquakes and
tsunamis. The Philippines, on the other hand, has had its
fair share of typhoons and tropical storms. Aside from
Ondoy, our country has experienced several devastating
typhoons. In the table below, we summarize some of the
most financially-damaging typhoons that our country has
dealt with

26. EFFECT ON THE STOCK MARKET
• Aside from the economic effects of typhoons and
floods, we also want to show the effect of natural
disasters on the stock market. A few days after
typhoons Milenyo and Ondoy, the PSE Index was
slightly down compared to where it was before the
typhoons occurred. Similarly, the PSE Index is down
0.4 percent, on lethargic trading, three days after
the peak of the recent rains and floods.

27. IMPACTS
• Natural disasters can have important
implications for public finance.
Disasters are likely to result in
additional expenditure and/or the
partial reallocation of already
committed financial resources, with
implications for planned investment
and other expenditures. Public
revenue may also decline as levels of
economic activity fall. In consequence,
a government may face increasing
budgetary pressures which could in
turn increase levels of domestic and/or
external borrowing or increasing the
money supply, each, in turn, with
potentially significant knock-on effects
(Benson and Clay, 2003).
FISCAL IMPACTS

28. M
I
T
I
G
A
T
I
O
N

29. • Know your enemy: hazards
and their effects
• Identifying which these are–
the elements most at risk–
indicates priorities for
mitigation.
• Vulnerability
• Tools, powers and budgets.
• PRECAUTIONARY
MEASURES
• Natural Disaster Reduction
Assessment
• POLICIES
• Suspension of Classes,
Work and Activities during
Typhoons
• DepEd Order No. 28 series of
2005: GUIDELINES ON THE
SUSPENSION OF CLASSES
WHEN TYPHOONS AND OTHER
CALAMITIES OCCUR.
• DEPED Order No. 50 s. 2007
with NDCC Memorandum No.7
s. 2006.
• Philippine Storm SIGNAL
WARNINGS (PSWS)

30. CONCLUSION/RECOMMENDATION
• Natural disasters, both natural and manmade, can and will occur,
often with little or no warning. It has tremendous effect not only
physically but also on the mental aspect of an individual especially
the younger ones. Disasters often strike without warning and
cause damages that limit or prevent an adequate response. We
have to commit ourselves to understanding these hazards and to
applying techniques that reduce our vulnerability. We need to
explore the feasibility of concerted scientific and engineering
efforts in reducing the loss of life and property through programs
of public education and of effective early warning system. The
development of warning systems with adequate range of
monitoring instruments for the purpose of collecting necessary
data and information for disaster evaluation is necessary for
establishing relative potential risks.

31. • The development of warning systems with adequate range
of monitoring instruments for the purpose of collecting
necessary data and information for disaster evaluation is
necessary for establishing relative potential risks.
Communicate knowledge for people to be aware and get
prepared on these hazards. Through public education,
introduce precautionary measures to have public
awareness on preparedness against these natural
hazards. Disasters are inevitable, predictable, and
expected; we must be ready to face them. The time has
come to fully develop technology for convenient and
immediate dissemination of warning system to the public.