Flood Danger : an Increasing Problem

With rainy seasons looming across Asia, typhoons and floods are not far behind. It pays to both understand, and be prepared for flooding, no matter where you live. By Henrylito D. Tacio

Manila, Philippines, 8 July 2018. With rainy seasons looming across Asia, typhoons and floods are not far behind: witness the recent devastation in Japan. But do you know what a flood is? Do you know what to look out for, how to cope and how to mop up? If not, here are a few pointers from the Philippines, where flooding is almost a part of life.

 Recent floods in Japan have caused countrywide destruction and havoc. Courtesy Phys.org

Recent floods in Japan have caused countrywide destruction and havoc. Courtesy Phys.org

Technically speaking, “… floods are due to the complex combination of weather, climatic and human activities,” says Rosalie C. Pagulayan, weather specialist at the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). And if we take the everyday news as an indicator, floods are increasing in both number and severity as both climate change and man-made interventions to geography cause greater problems.

 Rescuing flood victims from a rural village in Philippines. Courtesy IDS-Comval.

Rescuing flood victims from a rural village in Philippines. Courtesy IDS-Comval.

Nature-based floods can be precipitated by five weather-related disturbances such as thunderstorms, cold fronts, monsoons, intertropical convergence zones (ITCZs), and tropical cyclones. And obviously, as illustrated by areas of frequent flooding like the Ganges-Brahmaputra-Meghna Delta in Bangladesh, by the location and the topography of the country.

All these kinds of weather disturbances can result in the dumping of a lot of water over a short period of time, causing flooding in low-lying areas.  One of the worst floods in recent years occurred in Mumbai, India, when just under 1m of rain fell in 24hrs in July 2005. A similar thing happens when there is a storm surge, or a rise of seawater above the normal level, on the coast. This is usually generated by the action of the wind and atmospheric pressure, often associated with a tropical cyclone.

According to one PAGASA briefing paper, a storm surge can inundate low-lying coastal communities and cities by up to several metres, as the level of the ocean is rapidly raised.  This happened in Metro Manila in 2011, when large waves hammered the coastline of Manila Bay causing flash floods and portions of the sea wall to collapse. Similarly, high tides that coincide with high river flows from storms or excess rain can aggravate flooding near coasts.  Early this year, torrential rains inundated many areas in Davao City as Bankerohan River overflowed and submerged houses along river banks.

What to Do

PAGASA has addressed the issue of how to cope in a briefing paper that gives  some safety tips prior to flooding, during a flood, and after a flood.  Although not always easy to remember in the heat of the (wet) moment, here are some tips that can ease the situation, and even save lives.

  • Before flooding occurs, keep informed of the daily weather conditions and forecasts from a weather bureau.  That might mean also keeping a spare phone charged.
  • Be aware how often your location is likely to be flooded and to what extent; know the flood warning system and evacuation plan of your community and make sure your family knows them too.
  • Designate an evacuation area for the family and animals, and assign family members specific instructions and responsibilities according to an evacuation plan. 
  • Drinking water must be stored in containers as water services may be interrupted. 
  • Keep a stock of food which requires no or little cooking and refrigeration, which will last at least three days.  Also keep a portable radio and flashlight with spare batteries, emergency cooking equipment, candles, matches, and first aid kid hand in case of emergency.
  • Securely anchor weak building foundations and doorways. Sandbags or heavy bricks will help.
  • Important belongings should be moved to upper levels and pets/livestock taken to higher ground.
 In some cases, the real dangers only appear when the water goes down. Courtesy Henrylito Tacio.

In some cases, the real dangers only appear when the water goes down. Courtesy Henrylito Tacio.

If the worst happens and evacuation is ordered, it must be done quickly.  Don’t panic, and try to move to a safe area before access is cut-off by floodwaters.  And do remember to turn off main electricity switch and gas valve, and lock the building before evacuating. During the flood itself, stay indoors if at all possible.  Beware of drinking contaminated food and water. Don’t attempt to cross rivers or flowing streams where water is above your knee; the force may be stronger than you think.  Beware of water-covered roads and bridges.  And do not go boating in swollen rivers. 

After the flood, there are several things to remember: 

  • Re-enter buildings with caution, using electric flashlights; flammables and dangerous animals like water snakes may be inside. 
  • Be alert for fire and health hazards like broken electric wires, chemical contamination or simply trapped pools of water.. 
  • Do not eat food or drink water until they have been checked for flood water contamination.
  • Report broken utility lines (electricity, water, gas) to appropriate authorities. 
  • Do not turn on the main switch or use appliances and other equipment until they have been checked by competent electrician. 
  • Do not go “sight-seeing and selfie-taking” in disaster area; your presence might hamper rescue and other emergency operations

And know that floods can happen anytime, anywhere. Big cities are not immune. Listen to the woes of one flood victim: “The downpour of rain was unprecedented. It came without much warning. When we woke up in the morning, there was intermittent heavy rain and I thought that it was just seasonal – indeed the rain this year has all been unusually heavy, unlike during the last three years.  But then the water reached nearly one metre deep on the main streets. I couldn’t drive, there was water everywhere. We just had to wait for it to go down.”

As PAGASA’s Pagulayan puts it: “In any disaster, the first line of defense is still the awareness of the communities at risk." Worth remembering as the rain on the roof gets louder..