TYPHOON

Causes And Mechanisms, Impacts And Effects, And

Mitigation

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.

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)

• 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. 

• Variability in ActivityOn 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.

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, CAR, Ilocos region

Unding(Muifa)

November 14-26,2004

69 3.87 240 Bicol Region, MIMAROPA

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

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

CAUSES  OF TYPHOON TRANSFORMATION

Pre-conditions and Conditions of Typhoons

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.

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.

FRONTStall 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.

MESOSCALE CONVECTIVE SYSTEMThese 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.

7 BASINS WHERE TROPICAL CYCLONE DEVELOPS

• NORTH ATLANTIC OCEANJune 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.

• 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.

• 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.

THE LIFE OF A TYPHOON

THE FOUR STAGES OF THE LIFE OF A TYPHOON

•FORMATIVE STAGE

•IMMATURE STAGE

•MATURE STAGE

•DECAYING STAGE

EFFECTS OF TYPHOON

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.

TREES AND VEGETATION

WATERCRAFT AND WATER OPERATIONS

LIFE

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

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.

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

MITIGATION

• 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)

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.

• 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.