Season of floods begins

By Henrylito D. Tacio
“The rainy season has come once again and for many communities in the Philippines, this means getting ready for strong typhoons.” — Renee Juliene Karunungan, Advocacy Director of Dakila, an organization of artists working together creatively inspiring social transformation
 
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Three’s a company, so goes a popular saying.  So is disaster.  In the Philippines, disaster comes together in three: typhoon, rain, and flood.
Among the three disaster, flood tops.  Rain happens all the time.  Of the 20 tropical cyclones that hit the country every year, only 6-9 typhoons make landfall, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).  
But flood is a different story.  Once it takes place, no one can stop it.  Flood wreaks havoc not only to the surrounding that it passes through but also destroys home, buildings, bridges, and even takes lives.
The Department of Science and Technology (DOST) classified flood under the hydrometeorological hazard that also include tropical cyclone, storm surge and rain-induced landslide.
Volcanic eruption, landslide, earthquake and its related hazards (ground shaking, liquefaction, ground rupture, tsunami and landslide) are categorized under the geological hazard.
Flood — which comes from the Old English flod, a word common to Germanic languages — happens “when water from streams, rivers and other bodies of water overflow to low-lying areas due to heavy and prolonged rainfall and when rain waters are not drained rapidly due to inadequate or defective system or when coastal water rises due to high tide or storm surge.”
Rosalie C. Pagulayan, weather specialist II of PAGASA, said typhoons generally bring floods.  But typhoons are the not the only flood initiator.   “Floods are due to the complex combination of weather, climatic and human activities.  Most floods occur as a result of moderate-to-large-scale rainfall events,” she explained.
 
Weather disturbances
The Philippines, given the location and the topography of the country, experiences four other weather-causing phenomena which can bring floods.  These are: thunderstorms, cold front, monsoons, and intertropical convergence zone (ITCZ).  The weather bureau gives the following insights on the four phenomena: 
Thunderstorms, called local storms, occur when towering cumulus clouds reach a height where the temperature is well below the freezing point.  Among the associated hazards are heavy rain (which may cause flashflood) and lightning (which may cause death, burns or fire).
Cold front is formed when cold air moves over areas of warm air.  Since cold air is heavier than warm air, the warm air is pushed aloft by the cold air giving rise to widespread cloudiness.  The cold front affects the eastern part of the country from November to late April or early May.
There are two types of monsoon: Southwest and Northeast.  In the former, the Asiatic continent becomes warmer than the surrounding seas and a low pressure cell develops over the continent.  This causes a flow of moist southwest wind over the Philippine area. At times, when this southwest flow becomes thick in depth, it persists for a long period causing continuous rains which may last for weeks during the months of June to September.  The Southwest monsoon is responsible for the great portion of rainfall during the country’s wet season.
Known by sailors as the doldrums, the ITCZ is an area where the northern hemisphere trades meet the southern hemisphere trades.  According to the weather bureau, ITCZ is characterized by towering clouds of cumulonimbus clouds accompanied with showers of widespread thunderstorms.
“The axis of convergence, which is usually oriented in an east to west direction, does not remain stationery at the equator but migrates north or south of the equator,” a briefing paper from PAGASA explains.  In the Philippines, it oscillates during the months of May to October.
All these weather disturbances bring a lot of water causing flooding in affected areas. 
But there are also human activities that cause floods, according to the DOST-published book, Reference for Emergency and Disaster.  These are: increased urbanization and coastal development; indiscriminate dumping of garbage in waterways, canals and drainage systems; informal settlers constructing illegal structures along and on top of waterways; deforestation; blasting that causes landslides and damming of rivers; and failure of levees.
 
Damage and health effects
A really big flood can cause billions of pesos in damage to agriculture, infrastructure, loss of productivity in industry and commerce, not to mention loss of human lives.  Congested urban centers like Metro Manila could stand still for days.
“With too much rain and floods, agriculture production especially in flood-prone areas will be adversely affected with physical and economic losses,” pointed out Dr. Rafael D. Guerrero, former head of Philippine Council for Aquatic and Marine Research and Development. “Floods will wash away crops, hasten soil erosion and increase crop spoilage due to poor storage and distribution problems.”
The Department of Health said floods will accelerate food-borne and water-borne diseases. “Flooding can contaminate the public water through the disruption of water purification and sewage disposal systems, rupture of underground pipelines and storage tanks,” the health department said.
Using contaminated water can cause a wide spectrum of illnesses, among them: acute gastroenteritis, dysentery, typhoid fever, cholera, and hepatitis A.  “Foods that may have been in contact with contaminated floodwater should not be eaten,” the health department advised.
In addition, there is an increase of leptospirosis cases after heavy rains or flooding incidents.  This livestock disease transmissible to many may be acquired through wading in water contaminated with urine of infected animal.
Mosquito-borne diseases like dengue fever and malaria also rise with the increase in mosquito breeding grounds.  And with the cold weather also come airborne diseases like influenza, which spread fast in congested areas such as Metro Manila’s inner cities.
 
Flood safety rules
Because of these projected economic and health problems, PAGASA said that flood damage mitigation and protection should be a concern not only during the disaster but should be practiced before, during and after the occurrence of a flood.  As such, it issues the following flood safety rules:
Before the flood, a person must find out how often his location is likely to be flooded.  He should know the flood warning system (issued by PAGASA) in the community and inform the family about it.  The head of the family must know the daily weather condition.  He must designate an evacuation area for his family and the livestock.  In addition, he must assign family members instruction and responsibilities according to an evacuation plan.
In addition, people are advised to keep a stock of food which requires little cooking and refrigeration before the flood.  The following must be kept: transistorized radio and flash light with spare batteries, emergency cooking equipment, candles, matches, first aid kit, and water.
When warned of flood, everyone must watch for rapidly rising flood waters. The family should listen to the radio for emergency instructions.  If the head of the family finds it necessary to evacuate, then he must move them to a safe area before access is cut off by flood waters.  However, it is wise to turn off electricity at the main switch in the building before evacuating.  “Also lock your house before leaving,” the PAGASA suggested.
During the flood, the PAGASA advised to avoid areas subject to sudden flooding.  It cautions: do not attempt to cross rivers of flowing streams where water is above the knee; beware of water-covered roads and bridges; eat only well-cooked foods; and drink only bottled, boiled or treated water.
After the flood, the weather bureau recommended that you re-enter the house with caution using flashlight.  “Be alert for fire hazards like broken wires,” it warned.  “Do not eat food and drink water until they have been checked for flood water contamination.”
The PAGASA also suggested that broken utility lines (electricity, water, gas and telephone) be reported to appropriate agencies/authorities.  “Do not turn on the main switch or use appliances and other equipment until they have been checked by a competent electrician,” it said.
As floods are common throughout the country, the weather bureau has launched the Flood Early Warning System (FEWS) capacities.  It has five basic elements: prediction, detection, communication, decision-making, and mobilization.
“In any disaster of given magnitude, the first line of defense is still awareness of the communities at risk,” reminded Pagulayan. 
It’s rainy season once more.  As another saying goes, forearmed is forewarned.  Listen to the woes of one flood victim: “The downpour of rain is unprecedented. The rain came without much warning. When we woke up in the morning, there was intermittent heavy rain and I thought that it is seasonal – indeed the rainfall throughout this year has been quite heavy, unlike during the last three years.  The rain water reached two feet on the main streets. I couldn’t drive, there was water everywhere.”
Now, for our weather forecast!