Sinkholes

 A sinkhole is a depression in the ground that has no natural external surface drainage.
 Water drains to the subsurface

Causes of sinkholes
 Underneath soil/rock is dissolved by groundwater flowing through the material.
 Human involvement

Factors in sinkholes
1. Aquifer systems
 The soil above the system is balanced by the water pressure in the aquifer. When water is
removed from system it destabilizes the pressure, increasing the chance of a sinkhole forming
 Higher chance in urban
2. Karst Terrain
 landscape formed from the dissolution of soluble rocks like limestone and gypsum.
 characterized by sinkholes, caves, and underground drainage systems

Types of Sinkholes

1. Dissolution sinkholes
 ground with little overburden
 Water erodes the rock away
 deep impression in the ground forming a basin
2. Cover-collapse sinkhole
 Water erodes rock away underneath overburden
 Overburden soil loses stability
 Rapid and sudden collapse
 Can take weeks or years to reach point of collapse
3. Human involvement
 Leaky pipes
 Sewer leakage
 Pumping of groundwater
 Construction
 Water diversion
 These are majors in formation of a sinkhole
Most Effected Areas

- Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania are most prone.

Prevention of Sinkholes
 Natural Sinkholes are very hard to prevent

 Human made sinkholes can be avoidable

 Proper construction and maintenance of any underground pipes

 Proper groundwater usage

 Helps keep water table high and supports overburden

 When a sinkhole occurs make sure it is kept trash free

 Sinkholes usually have a direct link to drinking water which trash thrown into
the sinkhole can lead to pollution of drinking water.

Famous Sinkholes
 Guatemala City’s Sinkholes, Guatemala

 Happened in 2007, 300 ft. down

 Devil’s Sinkhole, Texas, U.S.A.

 40 ft. by 60 ft. opening , 400 ft. down

5 Mysterious Sinkhole in the Philippine you might not know.

MANILA, Philippines – The Mines and Geosciences Bureau (MGB) of the Department of Environment
and Natural Resources (DENR) has revealed at least 5 places in the country having sinkholes or hold the
potential for sinkhole formation. In the past years, some mysterious sinkholes were found in several
areas.

1. Sinkhole in Bantayan Island and Badian, Cebu

A new sinkhole in Sta. Fe town in Bantayan island was found in July last year that forced families
 in sitio Dapdap, Barangay Langub to relocate. Initially, the hole is two to three feet wide but
grew wider according to residents. The sinkhole was about 40 feet wide and 4 feet deep.
2. Sinkhole in Kabankalan City, Negros Occidental

Six people have reportedly fallen into a 12 feet deep sinkhole that suddenly appeared in the
middle of a basketball court in Purok Jalandoni, Barangay Oringao in Kabankalan City, Negros
Occidental in July lasy year. MGB said the hole may have been created by water flowing
underground. They considered this as a geological hazard.

3. Baguio City sinkholes

Sinkholes are quite common in Baguio City, which also has at least seven known faults and
numerous areas vulnerable to landslides. Landslides could be triggered by an earthquake or
continuous rainfall, which can also cause sinkholes to wreak havoc.

Because Baguio has one of the 10 highest daily rainfall records in the world and is visited by an
average of five cyclones in a three-year period, landslides and sinkhole-related mishaps are
expected.

4. Sinkhole in Bohol

The deep hole found in Barangay Cambilan, Catigbian, Bohol according to Harlans Multimedia
Production who has posted the video in Youtube said it was due to the 7.2 magnitude
earthquake that struck the province in October 2013.

5. Mysterious Underwater sinkhole of Dadiangas, GenSan

Disaster officials are still puzzled on a deep hole suspected sinkhole at Purok Tinago, a
community of informal settlers in Barangay South Dadiangas, General Santos City. Local TV
stations have reported that it suddenly appeared in February this year.

Local reports said the underwater hole continues to eat into the shores and gobble their homes.
When they tried to measure the depth of the hole using a pumpboat anchor, only 20 dipa
(fathoms) were left of the 350 fathoms of rope

HYDROMETREOLOGICAL HAZRAD

What is Typhoon?
❖ A typhoon is described as a “tumultuous storm” due to its large storm system that
moves in spiral or circular motion producing violent winds within hundreds of kilometers or
miles in diameter.

❖ Usually the wind moves around a region of low atmospheric pressure.

❖ Meteorologist also illustrates typhoons as a mature tropical cyclone that develops in the
western part of South Pacific Ocean known as the North-western Pacific Basin.
 ❖ Almost one third of the world’s yearly tropical cyclone originates in this basin making it
the most active tropical cyclone basin on Earth.

Typhoon and its origin:

❖ Hurricane - A virulent storm originating from the Atlantic Ocean and Eastern Pacific.

❖ Tropical Cyclones - if it originates in the Indian Ocean.

Typhoon as…

❖ In 1550, “tipon” is described as a violent storm”.

❖ “Whirlwind”, greek word based from a character personified as a giant, father of the
winds.

❖ The word “cyclone” was first recorded during a voyage of Caesar Frederick to the East
Indies.

❖ “Tai fung” Chinese word describing a “great wind”.

❖ “Toofan” Indian word pertaining to “big storm.”

❖ “Tufan” is an Arabic word, Persian and Hindi term meaning “big cyclonic storm”.

Terms used for Typhoon around the world:

❖ Filipinos refer to it as “Bagyo”.

❖ Australians called it “willie-willie”.

❖ South Americans refer to it as “tornado.”

❖ “Tropical Cyclone” is the term used for strong winds coming from Southeast and
Southwest Indian Ocean and Southwest Pacific Ocean.

❖ “Typhoon” is the term used in Northwest Pacific Ocean.

❖ “Hurricanes” is the term used in South Pacific Ocean and North Atlantic Ocean.

❖ “Severe Cyclonic Storm” is the term used in North Indian Ocean.

Typhoon in the Philippines:

❖ The Philippines experienced “bagyo” 12-20 times annually.

❖It is usually accompanied by strong winds, heavy rains and large ocean waves.

❖ Its wind circulation revolves to the right of Southern Hemisphere and to the left in the
Northern Hemisphere.

❖ PAGASA - The country’s premier agency for meteorological and hydrological hazards,
Philippine Atmospheric Geophysical & Astronomical Services Administration.

❖ PAGASA has independently named tropical cyclones entering Philippine Area of

Responsibility (PAR) since 1963. Following the American tradition of naming typhoon in
 alphabetical order, PAGASA had traditional utilized female name ending in “ng” until early 2000
when they started using male’s names.

Classification of Tropical Cyclones:

Four Components of Typhoon Configuration

❖ The eye of the typhoon is the center part which has the lowest pressure. There is
definite stillness of light wind about 20 kph. It generates a partly cloudy clear sky alternating
with thin clouds of 30 km average diameter.

❖ The eyewall is arrange band of clouds in the eye of a storm. It is the area with most
turbulent winds, an average of 8 to 40 km and strongest precipitate. Meteorologists expect its
typhoon force wind to be more than 118 kph.

❖ Inner rainbands are organized winds that move inwardly or spirally towards the center.
It generates an occasional precipitate with winds up to 63 to 117 kph and heavy squalls occur
every hour. It is characterized by atleast 90% sky coverage with soaring or far above the ground
clouds.

❖ The outer rainbands are dispersed outer spiral winds that moves inwardly. It generates
a placid to judicious rainfall with winds up to 62 kph and heavy squalls every 3 to 6 hours.
Sunlight is still evident with atleast 50% cloud coverage.

Cloud Description
❖ Okta is the amount of cloud coverage at any given area. The condition of the sky are
measured in terms of how many eighths of the sky are covered in cloud, from 0 okta or
completely clear sky to 8 okta or completely overcast sky.

AGE:
CLOUD COVERAGE:

Rain & Rainshowers Description

1. Rains

Defined as uninterrupted precipitation that has droplet of atleast 0.5mm or greater and last for
several hours.

Rain Classification

▪ Intermittent rains –come and go at interval.

▪ Frequent rains – continuous

▪ Widespread rains

▪ Occasional rains – isolated or random

▪ Monsoon rains - seasonal

▪ Heavy rains

▪ Moderate rains

▪ Light rains

▪ Very light rains

2. Rainshowers

Defined as a precipitation of short duration with abrupt start and hasty end but stronger
intensity.

Rainshowers Classification

▪ Squally rainshowers – stormy or violent

▪ Occasional rainshowers - random

▪ Isolated rainshowers – less than 1/8 coverage

▪ Scattered rainshowers
Measures that can be taken BEFORE a typhoon:
1. It is vital to constantly keep yourself updated with the up-to-the-minute weather
reports. Being abreast with the latest weather bulletins and official government announcements
and warnings are paramount to prepare yourself and your family for the typhoon.

2. Stay connected with family member. Prior to any weather disturbance make an
emergency plan with your family. Decide a pre-destined meeting place. Charge all modes of
communication.

3. Clean and unclogged all drainage system of your house. Check your roofings, windows,
doors and ceilings of any holes or dents. Trim or cut trees.

4. Prepared ample amount of imperishable no cook food and bottled water.

5. Transfer all your furniture, appliances and other stuff not viable to come in contact with
water to an elevated portion of your house.

Measures that can be taken BEFORE a typhoon:

6. If your local official advised to evacuate, do so. Do not wait for any untoward incident to
happen before leaving. Your mantra should be “better safe than sorry.”

7. Your emergency kit should be ready at all times. It must contain first-aid supplies, life
vest, transistor radio, flashlight, candles, match, toiletries, alcohol and clean clothes.

8. Secure all important family documents by wrapping in with plastic and include it in you
go bag.

9. Use water-proof shoes to prevent fungal infection.

10. Farmer should harvest crops days before the weather disturbance.

Fishermen should refrain from fishing and must secure their boats at bay.

Measures that can be taken DURING a typhoon:

1. Stay inside your house. Postpone any schedule of travels.

2. Be aware of areas vulnerable to floods and landslides. Stay away from these area as
much as possible.

3. Keep updated with the latest news through your television, radio and internet.

4. Avoid drinking from sources exposed to flood water. Boil water for at least 20 minutes.

5. In case of power interruption, place all lighted candles and lamps away from curtains
and flammable materials.

6. Shut down the main source of electricity if flood water is rising. Secure your electronic
gadgets and appliances in high grounds.

7. Do not stride in flood water to avoid having water-borne diseases. Use protective
clothing like raincoats or plastic boots.

8. If advice to evacuate, do so promptly. Do not wait for the situation to worsen. Secure
your house for any burglar.
 9. People living in areas vulnerable to storm surge should evacuate in high grounds ahead
of time. Ask local officials for the nearest evacuation area.

Measures that can be taken AFTER a typhoon:

1. Keep abreast with the latest weather update through radio, television or internet.

2. If your house is heavily damaged, stay in the evacuation center until advice to go home
or have your house inspect by city engineers.

3. Do not use wet electrical outlet. Ask an electrician to inspect all electrical outlet before
using it again. All wet appliances must be disposed.

4. Never exposed open wounds to flood water. Water-borne diseases like Leptospirosis are
rampant during this season.

5. Boil water at least 20 minutes before drinking it.

6. Old tires, cans and pots must be clean thoroughly or disposed. These could be breeding
ground for mosquitoes.

7. Be cautious for harmful animals like snakes that may have entered your house.

8. Report broken electrical cables and plummeted electrical post to utility services.

9. Do not hinder emergency and rescue operations.

Typhoon Hazards:
The following are common hazards associated with typhoons:

1. Coastal Flooding and Storm Surge

2. Strong/High Winds

3. Heavy Rainfall & Inland Flooding

4. Mudslides, Landslides, or Mudflows

What is Thunderstorm?
❖ A type of storm illustrated by the occurrence of lightning and its acoustic effect on the
Earth’s atmosphere is known as thunderstorm.

❖ It is also known as lightning storm, electrical storm and thundershowers.

❖ It is typically exemplified with heavy rains accompanied with thunder.

❖ Given that thunder is a result of lightning, all thunderstorms have lightning.

❖ Thunderstorms happen commonly with the cumulonimbus clouds generating gusty

winds, heavy rains and occasionally hail.

❖ The archetypal thunderstorm is 15 miles in diameter and last for about 30 minutes.
3 stages of Thunderstorm Development:
❖ The initial stage is identified as Cumulus Stage.

➢ When the sun warms the earth’s exterior, the ground heats the air above it. The warm
air increases and water vapor concentrates to a towering cumulus clouds which could ascend a
height of 8-10 km.

❖ The second stage is called Maturing Stage.

➢ It is where clouds can generate heavy rains, relentless lightning, strong and gusty winds,
hail and sometimes tornadoes. It is at this stage where thunderstorm is at its strongest.

❖ The Dissipating Stage

➢ is when precipitation decreases its intensity and clouds begin to dissipate. Some
thunderstorm produces a burst of strong winds and lightning lingers risk during this stage.

Signs of impending Thunderstorms:

1.Towering cumulous clouds

2. Shadows of dark skies

3. Sparks of lightning, and gusty winds

4. Roar of thunder, and

5. Static on you communication gadget

Measure that can be taken BEFORE a thunderstorm:

1. Create an emergency communication plan with your family and prepare your
emergency kit.

2. Toppled down tree branches near your house which could start up fire if struck with
lightning.

3. Put off scheduled outdoor activities. Keep in mind the 30/30 Lightning Safety Rule:
 Then lightning struck, thunder will be heard less than the count of 30. Wait for at least 30
minutes before leaving the house after hearing the last thunder strike.

4. Turn off all electrical appliances before the storm strikes to avert power surges.

Measures that can be taken DURING a thunderstorm:

1. Stay away from open portions of the house like windows, doors or porches. Do not lie
nor lean on concrete walls.

2. Avoid using any communication lines, you can get electrocuted. Stay away with
electrical equipment or cords. Unplug all electrical items. Power surges from lightning can cause
severe damage.

3. Keep off from sinks, faucets and bathtubs. Do not wash your hands, do the dishes,
laundry nor take a shower. Plumbing and bathroom equipment can conduct electricity.

4. If you are near any body of water, go to the near land area and take refuge inside a
building than any vehicle.

5. If you are inside a vehicle, lock the windows. Park to a safe corner and wait until the
rains stop. Do not park your vehicle near trees.

6. If you are driving, stop the vehicle at once and park at the safest possible area. Turn on
the emergency flashers until the rains stop. Do not touch metal or other surfaces that are
capable of conducting electricity.

7. If you are outdoors, look for an elevated place free of flood. Stay away from tall
structures such as, trees, telephone lines, electric post and towers.

8. Keep off from open fields, hill tops, beaches.

9. Avoid close contact with any metal objects such as farm equipments, golf carts, bicycles,
tractors.

10. Do the squatting and tucked in position. Position your hands on your knees with your
head tucked between. Try to contact as little of your body to the floor as possible. Do not lie flat
on the floor. Fully extended body is more to electricity.

Measures that can be taken AFTER a thunderstorm:

1. Keep off from storm-affected areas.

2. Lend a hand people who needs special support, such as infants, children and the elderly
or those with access or functional needs.

3. Report immediately damaged electrical posts and cables.

4. Watch your animals closely. Keep them under your direct control.

5. If you or someone you know has been struck by lightning, call the authority
immediately.

6. People or objects hit by lightning does not transmit electrical charge, never be afraid to
touch or assist them. Assist in life-giving measures when necessary. Burn victims must be rush to
the nearest hospital.
Thunderstorm Hazards:
1. Lightning

2. Heavy rains/ precipitation

3. Flash Flood

4. Tornadoes/ waterspouts

5. Hail

FLOOD AND FLASHFLOOD

What is a Flood?

❖ The Philippines as an archipelago, is surrounded with abundant body of water such as

oceans, rivers, lakes and streams.

❖ Flood, a perennial problem of Filipinos due to frequent monsoon rains, cyclones,

thunderstorms, ITCZ, etc.

❖ These hyrometeorological hazards are capable of generating large amount of

precipitation that pour to the heavily clogged sewerage systems of the metropolis causing the
unnecessary water surplus.

❖ Flood basically means an overflowing of water from streams and other bodies of water
or an accumulation of rainwater in low-lying areas.

❖ A flood is a transitory pour out of a normally waterless area due to spill over of a body of
water, remarkable build up, run off of surface waters or atypical erosion or destabilization of
shoreline.

❖ Floods can also be overflow of mud flow caused by buildup of water underground.

Two major categories of based on it causes:

I. Natural Causes

❖ a. Heavy and extended rainfall – Hydrometeorological disturbances such as tropical

cyclones, low pressure areas, inter tropical convergence zone, cold fronts and monsoons could
lead to heavy floodings.

❖ b. Storm Surge – It can generate elevation of ocean level to ground height to several
feet and flood nearby low-lying coastal communities.

❖ c. High Tide – that coincides with high stream flows can aggravate flooding near the
coast.
 II. Man-Made Causes

❖ a. Infrastructure and coastal development – It increases the resistance of ground

surfaces due to concrete roads and loss its ability to soak up flood waters and may result to flash
flooding.

❖ b. Haphazard dumping of garbage – It causes blockage of waterways.

❖ c. Blasting – generates landslides in the slopes of hills and mountains and may result to
unintended damning of rivers and streams.

❖ d. Informal settlers – intrusion of waterways can hinder the normal flow of floodwater.

❖ e. Deforestation – decreases the permeation capacity and speed of the flood flows.

❖ f. Failure of levees and dams – can produce the worst flood events by releasing large
quantities of water.

Floods can be classified according to the magnitude and depth of

damage:
1. Minor Flooding – flooding that may or may not be cause by overbanking. It could be
simply due to build up of unwarranted surface overflow water in flat low-lying areas. Flood
water is usually confined along river beds and low-lying areas of the metropolis.

2. Major Flooding – flooding is a result of overflowing rivers and lakes; serious damage
from major water reservoir likes dams, dikes or levees; Flood waters affects many neighborhood
and stretch rapidly to adjacent shoreline of comparatively lower elevation. There is a persistent
water current in some areas particularly seem in deep flooding.

What is a Flash flood?

❖ Normally floods take about 12 to 24 hours or longer to develop after an intense
downpour. But there is a particular type which develops in less than 6 hours commonly termed
as “flash floods”.

❖ Flash floods build up in areas with steep slopes of rivers.

❖ Its rapid development is mainly caused by remarkably limited time for drainage
catchment.

Effects of Flooding:
❖ unwarranted destructions of road and rail network and bridges, buildings and other
economic infrastructure.

❖ slaughter of agricultural crops and livestock’s, failure of productivity in industry,

commerce and trade.

❖ the incalculable loss of human.

❖ socioeconomic problems of forced human displacement and the emotional impact on

those affected by floods.
 ❖ shortage of needed utilities and indispensable necessities, particularly, food and clean
water.

❖ epidemic of Gastro-intestinal diseases frequently breaks out.

❖ Respiratory ailments due to exposure are also quite common.

Measures that can be taken BEFORE flood:

1.If you are new in the area. Ask neighbors or local officials the likelihood of your area to be
flooded.

2. Be informed of the flood warning system of your community.

3. Be updated with the daily weather condition.

4. Look for an evacuation area for your family and pets

5. Designate responsibilities with each of the family member in your emergency rescue
plan.

6. Prepare imperishable food and bottled water for atleast 2 to 3 days.

7. Have a transistor radio with batteries to listen to weather or flood advisory. 8. Prepare
emergency lights, flashlights, cooking equipments and first aid kit.

9. Elevate appliances and other electrical gadgets.

10. Safeguard your house from harmful rodents that might enter together with flood water.

When Warned of Flood:

1. Monitor rise in water level. Evacuate immediately when necessary.

2. Keep updated with any emergency instructions from your local officials.

3. Store drinking water.

4. Safeguard important documents.

5. Transfer livestock and pets to higher ground. 6. Turn off main electrical switch of your
house.

7. Secure your house by locking the door.

Measures that can be taken DURING flood:

1. Stay inside your house or the evacuation area.

2. Avoid low-lying areas.

3. Stay away from any body of water like rivers, lakes, and dams.

4. Use protective clothing when walking water-covered roads and bridges.

5. Never attempt to swim flood water

6. Be cautious of contaminated food and water.

Measures that can be taken AFTER flood:
1. Return to your houses only when it is safe.

2. Be aware of damaged electrical wirings.

3. Do not eat food nor drink water soaked in flood waters.

4. Inform your utility services of damaged electrical or telephone cables.

5. Never turn on electrical appliances nor communication gadgets unless checked by

licensed electrician.

6. Consult physician if there are signs and symptoms of waterborne diseases.

7. Never hamper the search and rescue operation of your local officials.

Measures that can be taken to MITIGATE floods:

1. Help in reforestation measures of the government.

2. Report illegal loggers and people participating in “kaingin”

3. Informed local officials of unauthorized constructions of fish ponds.

4. Practice proper garbage disposal.

5. Support clean up drives of rivers, esteros and watersheds.

6. Participate in the flood mitigation efforts of the local government.

7. Make your drainage free from trash.

What is a Storm Surge?

❖ During a tropical cyclone it is common for ocean waves to be pushed towards the shore
by the force of the wind and the intense pressure of a heavy down pour.

❖ This is occurrence is known as “storm surge” or “daluyong ng bagyo” in the vernacular.

❖ Meteorologist defined storm surge as an unusual ascend of water during a typhoon,

over and above the calculated high wave. ❖Storm tide, on the other hand, is the elevation of
water level during a typhoon caused by both high tide and storm surge.

❖ Storm surge is a direct result of strong winds during a tropical storm or hurricane.

❖ Coastal Flooding is a direct result of storm surge beside quarters with shallow shorelines
or beach-front areas.

❖ Last 2012, Typhoon Pedring hit the metropolis flooding the areas along Roxas Boulevard
in Manila, destroying the sea walls and structures along Manila Bay.

❖ Storm surges can set off flooding coastal areas 3 to 6 hours prior to landfall. On
highspeed moving typhoons storm surge can occur extremely fast.

❖ A Super Typhoon can spawn storm surge elevation of more than 20 feet above sea level.
Factors that Cause Storm Surge:
❖ Wind/ Pressure Effect – Winds is directly proportional to storm surge and inversely
proportional to atmospheric pressure. The stronger the winds of a typhoon and the higher the
peak of storm surge and the lower the atmospheric pressure.

❖ Rain Fall Effect – Heavy precipitation caused by typhoons increases the total surge
height near the coast.

❖ Tidal Effect – If the storm surge coincides with the occurrence of astronomical tide,
surge height will be higher.

❖ Shape of the Coastline – The gentler is the slope, the higher is the surge in the coastal
areas.

Measures to be taken BEFORE a Typhoon:

1. Prepare an emergency kit and emergency rescue plan.

2. Assess your area. If you live in low-lying area, evacuate immediately.

3. People near dams and other water reservoir must monitor the safety of their area.

4. Listen to official announcements of the local government regarding evacuation plan of

your community.

5. Valuable possession must be secured in the emergency kit.

6. Strengthen roofing.

7. Cut down tree if it posed danger. Secure permit from DENR.

8. Unclog rain gutters and downspouts.

9. Secure outdoor furniture, decorations and garbage can inside the house.

10. Ask your local officials for availability of rescue boats.

Measures to be taken DURING a Storm Surge:

1. Be informed of the latest news by listening on radios or watching TV.

2. All outdoors equipments should be secure by bring it inside the house.

3. Turned off electrical breakers. Do not use lines of communication if not necessary.

4. Ensure supply of water by filling up bottles, tubs, containers etc.

5. Place food supply in safe containers

6. Evacuate immediately when advice by local authorities and under the following
circumstances:

a. If you live near bodies of water or your house is made of light materials.

b. If you live condominium transfer to lower floors.

 7. Do not travel unless necessary.

8. Do not use the elevators.

Measures to be taken AFTER a Typhoon:

1. Keep updated to the latest news thru radio, TV or internet.

2. Stay safe inside your house hours after the storm surge.

3. If you cannot find your family member in the evacuation center, try your family
communication plan.

4. Never return to your house unless your local official says it is safe.

5. Avoid any forms of travel.

6. Stay away from exposed electrical wirings and report it immediately to your utility
company.

7. Check loose electrical wirings, gas leaks and damages inside your house.

8. Stay away from buildings that posed danger. Ask your local officials for assistance.

9. Never use candle. Emergency lights and flashlights is safer.

10. Inspect your house from any harmful animal that might have entered.

11. Watch out for falling debris.

12. Make sure that your drinking water and food is not contaminated.

13. Discard spoil food.

14. Use protective clothing like plastic boots, goggles, rain coats.

15. Never use your telephone unless by utility service. You might get electrocuted.

El Niño and La Niña El Niño

❖ El Niño Phenomenon is the extreme warming of sea surface that develops in the Pacific
Ocean that usually causes heavy rains in some parts of the world and drought in other parts.

❖ El Niño, a Spanish term meaning “Little Child” or “Boy Child” was previously considered
a local event along the coast of South American countries.

❖ It was the term used by Peruvian fishermen in describing the warm ocean current
flowing along its coast around Christmas season.

❖ It occurs in the Pacific bowl every 2 to 9 years.

❖ In general, the weather phenomenon brings drought in the country with the following

Climatic abnormalities that indicate the occurrence of El Nino

Phenomenon in the Philippines includes:
(1) Late onset of rainy season;
 (2) Early cessation of rainy season;

(3) Weak monsoon activity;

(4) Isolated rain with short duration;

(5) Weak tropical cyclone activity;

(6) Far tropical cyclone track;

(7) Few number of tropical cyclone track;

(8) Few number of tropical cyclones entering Philippine Area of Responsibility;

(9) Less intense tropical cyclones.

Ill-effects of El Niño:
❖ degradation of soil, fire, water shortage.

❖ food shortage,

❖ power interruption,

❖ unemployment,

❖ migration to urban communities and ❖different health concerns.

La Niña
• On the other hand, La Niña, Spanish term for “Little Girl” is a phenomenon linked to a
change in atmospheric pressure known as Southern Oscillation.

• Recognized as “El Viejo” (Old Man) in some Spanish speaking countries, this event is
typified by bizarrely freezing ocean temperatures increasing rainfall over the western half of
Pacific

Ocean.

• La Niña brings unseasonal heavy rains and intensifies other hydrometeorological

hazards.

El Nino and La Nina El Nino and La

Nina
• An important atmospheric variation that has an average period of three to seven years.

• Goes between El Nino, Neutral, and La Nina (ENSO cycle, El Nino Southern Oscillation)

• Has large influence both in the tropics and midlatitudes.

• Main source of forecast skill beyond a few weeks.

 • El Niño is the extreme warming of sea surface that develops in the Pacific ocean that
usually causes heavy rains in some parts of the world and drought in other parts.

• Sea surface temperatures (SST) remain +0.5 to +1.5ºC above-average across much of the
equatorial Pacific Ocean.

• Based on current observations and dynamical model forecasts, El Niño is expected to

strengthen and last through the Northern Hemisphere winter

2009-10.

• El Niño a Spanish term meaning “Little Child” or Boy Child” was previously considered a
local event along the coast of South American countries.

• It occurs in the Pacific bowl every 2 to 9 years.

• Climatic abnormalities that indicate the occurrence of El Nino Phenomenon in the

Philippines includes

• 1. Late onset of rainy season

• 2. Early cessation of rainy season

• 3. Weak monsoon activity

• 4. Isolated rain with short duration

• 5. weak tropical cyclone activity

Why do we care?
• The circulations in the midlatitudes are substantially different in El Nino, Neutral, and La
Nina years.

• Since the temperature of the tropical Pacific changes relatively slowly, this gives some
meteorologist some insights into the weather over the next several months.

El Nino – weak Aleutian High

La Nina – strong Aleutian High

Thunderstorm Life Cycle

• Towering Cumulus Stage

– Cumulus clouds build vertically and laterally, and surge upward to altitudes of 8,000-
10,000 m (26,000-33,000 ft) over a period of 10-15 minutes

– Produced by convection within the atmosphere

• Free convection – triggered by intense solar heating of Earth’s surface – Generally not
powerful enough to produce thunderstorms
• Forced convection – orographic uplift or converging winds strengthen convection

– This is generally the cause of thunderstorms

– Latent heat released during condensation adds to buoyancy

– During the cumulus stage, the updraft is strong enough to keep water droplets and ice
crystals suspended

• As a result, precipitation does not occur in the cumulus stage

Thunderstorm Life Cycle

• Mature Stage – maximum intensity

– Stage typically lasts about 10-20 minutes

– Begins when precipitation reaches Earth’s surface

– Features heaviest rain, frequent lightning, strong surface winds, and possible tornadoes

– Weight of droplets and ice crystals overcome the updraft

– Downdraft created when precipitation descending through the cloud drags the adjacent
air downward

• Entrained dry air at the edge of the cloud leads to evaporative cooling, which weakens
the buoyant uplift and strengthens the downdraft

• At the surface, the leading edge of downdraft air resembles a miniature cold front and is
called a gust front

• Ominous-appearing low clouds associated with a gust front include a roll cloud and a
shelf cloud

Thunderstorm Life Cycle

Thunderstorm cells can develop along cumulonimbus cloud reaches the the gust front ahead
of the main tropopause, it spreads out forming a flat thunderstorm. The radar image shows
anvil top. Cloud tops during the mature up as an arc-shaped band. stage can build
to altitudes in excess of 18,000 m (about 60,000 ft).

Thunderstorm Life Cycle

In this visible satellite image, clusters of intense thunderstorm cells appear as bright white
blotches over portions of Texas, Oklahoma, and Missouri

Thunderstorm Life Cycle

• Dissipating Stage

– Precipitation and the downdraft spread throughout the thunderstorm cell, heralding the
cell’s demise

– Subsiding air replaces the updraft and cuts off the supply of moisture

– Adiabatic compression warms the subsiding air and the clouds gradually vaporize
 Thunderstorm Classification

• Thunderstorms are meso-scale convective systems (MCS) and are classified based on
the number, organization, and intensity of their constituent cells

• Single-cell thunderstorms

– Usually a relatively a weak system forming along a boundary within an air mass (i.e.,
gust front)

– Typically completes its life cycle in 30 minutes or less

• Multicellular thunderstorms

– Characterizes most thunderstorms. Each cell may be at a different stage in its life cycle,
and a succession of cells is responsible for a prolonged period of thunderstorm weather.

– Two types:

• Squall line

• Mesoscale convective complex

• Either can produce severe weather

Thunderstorm Classification
• Multicellular thunderstorm types

– Squall line – elongated cluster of thunderstorm cells that is accompanied by a continuous gust
front at the line’s leading edge

• Most likely to develop in the warm southeast sector of a mature extra-tropical cyclone,
ahead of and parallel to the cold front

– Mesocyclone convective complex (MCC)

• A nearly circular cluster of many interacting thunderstorm cells with a lifetime of at least
6 hrs, and often 12-24 hrs

• Thousands of times larger than a single cell

• Primarily warm season phenomena (March – September)

• Usually develop at night over the eastern 2/3 of the U.S.

• Is not associated with a front

• Usually develops during weak synoptic-scale flow, often develops near an upper-level
ridge of high pressure, and on the cool side of a stationary front

• A low level jet feeds warm humid air into the system

– Supercell thunderstorms are long-lived single cell storms

 • Exceptionally strong updraft, with rotational circulation that may evolve into a tornad

Thunderstorm Hazards
• Lightning, continued – What causes lightning?

• Large differences in electrical charge develop within a cloud, between clouds, or

between a cloud and the ground

– Upper portion and much smaller region of the cumulonimbus cloud become positively
charged, with a disk-shaped zone of negative charge in between. A positive charge is induced
on the ground directly under the cloud

• Lightning may forge a path between oppositely charged regions

• Charge separation within a cloud may be due to collisions between descending graupel
striking smaller ice crystals in their path. At temperatures < -15 °C (5 °F) graupel become
negatively charged while ice crystals become positively charged. Vigorous updrafts carry ice
crystals to upper portions of the cloud.

• Positive charge near cloud base also due to graupel-ice crystal collision, but temps > -15
°C (5 °F) induce positive charge to graupel and negative charge to ice crystal

Thunderstorm Hazards
• Lightning, continued

– A cloud-to-ground lightning flash involves a regular sequence of events

• Stepped ladders: streams of electrons surge from the cloud base to the ground in
discrete steps

• Return stroke: forms as an ascending electric current when the positive and negative
charges recombine; often emanates from tall, pointed structures

• Dart leaders, subsequent surges of electrons from the cloud, follow the same
conducting path

• Sequence takes place in < two-tenths of a second

– Lightning causes intense heating of air so rapidly that air density cannot initially respond

• Shock wave is generated and propagates outward, producing sound waves heard as
thunder

– Flash-to-bang method: Thunder takes about 3 seconds to travel 1 km (or 5 seconds to

travel 1 mi)

• If you must wait 9 seconds between lightning flash and thunderclap, the lightning is
about 3 km (1.8 mi) away

Thunderstorms

• A cumulonimbus with lightning and thunder!

• Deep layer of conditionally unstable air is necessary to produce a thunderstorm.

Several types of thunderstorms.

1. Single Cell,
2. Multicell,
3. Squall Line,
4. Mesoscale Convective Complexes,
5. Supercells

• Pose major hazards to public and economy. Lightning, Hail, Microburst Winds,

Flash Flooding, Tornadoes Lightning Basics

• What is lightning?
 An electric discharge, or spark, that occurs in thunderstorms (usually)
 80% occurs within clouds
 20% occurs between cloud and ground

• Lightning is ubiquitous, with more than

 6,000 ground strikes per minute from

 40,000 thunderstorms per day worldwide

Charge Separation
 Lightning requires the separation of different charges into different regions of a cloud.
 How does charge separation in clouds occur?
 We don’t know for certain, but we observe this: Lightning only occurs in cold clouds with
supercooled droplets and temps below 5oF.
 Thus, the ice crystal processes responsible for precipitation in cold clouds likely plays an critical
role in charge separation.

Charge Separation: One Theory

 Hailstones are covered by a layer of liquid water.
 The thin layer of liquid is positively charged.
 When hailstones and ice crystals collide, some of liquid molecules stick to the ice crystals.
 Along with the mass transfer, positive ions transfer from the hailstones to the ice crystals.
 The heavier, negative hail falls to cloud bottom.
 The lighter, positive ice crystals drift to cloud top.
 Produces negative lower, positive upper cloud.

Lightning Stroke
Cloud-Ground Sequence

1) Downward stepped leader. Stepped leader is invisible.

2) Upward return stroke.

3) Downward dart leaders.

4) Upward return strokes.

Dart leaders-return strokes:

 up to 25 cycles, 3-4 usually. Ground strikes are usually negative, that is electrons flow from
cloud to ground.
 Williams, The Weather Book

Summary: Key Points

• Lightning - electric discharge in thunderstorms

80% within clouds, 20% cloud to ground

• Lightning is ubiquitous, with more than 6,000 cloud-to-ground strikes per minute from more
than 40,000 thunderstorms per day worldwide.

• Lightning requires the separation of different charges into different regions of cloud.

• Charge separation maintains the earth’s fair weather electric field.

The State and its Citizen in Disaster

 REPUBLIC ACT NO. 10639
 AN ACT MANDATING THE TELECOMMUNICATIONS SERVICE
 PROVIDERS TO SEND FREE MOBILE ALERTS IN THE EVENT OF
 NATURAL AND MAN-MADE DISASTERS AND CALAMITIES
Section 1. Short Title. – This Act shall be known as "The Free Mobile Disaster Alerts Act".

Section 3. Definition of Terms. –

(a) Mobile phone service provider, service provider or telecommunication company refers to any
person, firm or partnership or corporation, government or private, granted a legislative franchise by
Congress to provide cellular mobile telephone services to the general public, and issued a certificate of
public convenience and necessity (CPCN) by the National Telecommunications Commission (NTC)
Project NOAH
 is the government’s flagship program for disaster prevention and mitigation which aims to
create a disaster-free Philippines by providing tools and information to mitigate or avert
disasters caused by natural hazards.
 Since its inclusion in the NDRRMC’s Pre-Disaster Risk Assessment system, Project
 NOAH has been instrumental in identifying areas that would be hit by hazards brought about by
extreme weather events. In line with the NDRRMC’s principle that
 warnings should be “hazard-specific, area-focused, and time bound,” Project NOAH has had
great success in determining which hazards would hit specific areas at
 particular times. We can count on more successes with the introduction of the newest platform
designed to provide more scientific information and a better user experience.

PROJECT DINA
 The Philippines, one of the signatory countries in the Hyogo Framework of Action (HFA), has
been constantly seeking for innovative means to educate the general populace in response to
HFA’s Priority Action 3: Use knowledge, innovation and education to build a culture of safety
and resilience at all levels.
 The Disaster Information for Nationwide Awareness
 Project or Project DINA is the Philippines’ proof of commitment to the realization of the HFA’s
priority action 3.
 Project DINA paves the way for the public exposition and access of disaster risk reduction and
management (DRRM) information materials. The project showcases a number of audio–visual
presentations (AVPs) which discuss DRRM topics, enabling the public to undergo online DRRM–
related instruction. Through this system, the public can gain disaster preparedness knowledge
on what to do before, during and after the following hazards