Flood and flash-flood are nothing new. They are old as elements and topography of planet Earth. If there are things notable with them, they could be in the change of degrees or circumstances about them, brought about by changes in time. Like, the Earth is believed to be warming, which is believed the cause of weather abnormalities among the effects.
Forests are effective watersheds. They hold rain water, releasing them to creeks and rivers as water seeks its own level – the ocean, gradually.
When a forest is gone it means more volume of water goes to the river in a shorter time – or at a flash. Gone forests means more frequent and bigger flash-floods.
As been stated, flash-flood is nothing new. Even in heavily forested areas with excellent watersheds they happen. Once in a while we get to hear mountaineers killed by flash-flood during storm, or while on a trek. Flushing effect of water is determined by height and run of the river i.e. the higher is the elevation of an area of rainfall and the shorter the run of the river to the sea, means a more turbulent river.
I was mountaineering when I was young. I’ve frequented Candoni and Tapi areas in southern Negros Island when I was 17. I’ve gone all over Negros’ frontiers when I was in my early 20s. Mine was more of treks in the wilderness than climbing tall mountains.
In between two hills is always a creek feed by rain and springs. In between two hilly or mountainous regions is a river feed by creeks. Many such rivers are tributary of a bigger river. Like, Magballo river is one tributary of the great Tabla river that is one tributary of the greater Ilog river. Wawa [Montalban] river is a tributary of Marikina river that is a tributary of Pasig river.
The line forming a triangle by connecting height and run is called a Flight. There may be areas along a river where river flight is stiffer. These are flash-flood prone points or stretches. Sometimes flash-flood can come in seemingly fine weather especially during monsoon season. Heavy downpour can happen in upper land that may not be noticed by people in the lower lands. People were known caught off guard by flash-floods. If you are in a mountain trek you should be aware of such danger. Trailways are usually along rivers and creeks. Because, people have found it convenient to move along creeks and rivers than hacking one’s way through thickets and wild.
Just about a month ago, tourists among them French and Italian nationals and their guide, if I remember right one TV report, were killed by flash-flood while on a trek to Mt. Pinatubo. [Apparently, guide gambled with everybody’s life. A locale, he must have known better.]
Flash-flood prone areas are usually, by appearance, characterized by rocks, boulders, and stones. Nice crossings in these areas as they are usually shallower. Seemingly convenient, nice place to make camp, too, as they look cleaner. But it could be like camping on a street before the city comes to life!
Take note of the highest watermarks of the river when you are on a trek.
A flash-flood is heralded by a strange rumbling coming from up-river, actually. But you need familiarization of the local area to be sure about that. It just might be some natural rapids or falls nearby and not a flash-flood you heard.
Before crossing, see that the water is clear, free of any floating debris. In the forest, water can become murky or clear, faster than many people have imagined. They are normally settled water because what falls and floats in there have readily been caught or “filtered” along the way. Murky or fast turning murky water and floating debris are abnormal. They are not good signs. If you are in the act of crossing or following a trail in such condition, get out-of-the-way fast, you could possibly get flushed! A flash-flood thigh deep can kill.
Daludo [Hiligaynon, Flash-flood] comes and goes fast. They could be over in a few hours. A day or a week is simply considered baha [flood] i.e. the river is flooded. When you’re at a crossing and the river is murky or flooded you may plant some stick, maybe tie a grass ribbon or make knot or notch to it, to mark water level. That’s to know if flood is coming or leaving, whether you should wait or not judging by the rate [of drop or climb] of murky water level.
If you happen to wait and someone, perhaps no more than a boy came, took off his clothes, tied them around his head, and soon he was a bobbling head you saw among the waves…but then he made it to the other side like no sweat, put on his clothes and went on his way like the whole exercise was nothing, well, he was born in there. Never, ever, think of trying it! You’ll probably only get yourself in the same side of the river somewhere downstream, glad to have somehow made it back to the riverbank to mind whatever were washed away and lost, or to mind a lot of dirty water swallowed…At least you were alive and you won’t believe it, or why you tried it!
What the boy did, actually, was to manage his head above turbulent water, while at the same time managed him in a way that he was floated and drifted by strong current towards the other side of the river, and not really swimming that we know. Freestyle, backstroke, butterfly, doggie, or whatever, are almost totally useless in there. With a little practice maybe they are adaptable, but the idea of swimming across a raging flood is crazy. It must be like running with the bulls in Spain! Keeping afloat is also harder because of less buoyancy of rain water compared to brackish and salt waters.
Sometimes rain comes intermittent for days so does seemingly endless flood. And sometimes flood can act like the graph in a stock market.
River may run through plains along its course. These stretches can flood but they, usually, are more gradually flooded as water volume is dispersed over a wider area as the river overflows. Water has a tendency to slow or stagnate in there because of a more vertical pull of gravity to it, at there.
Yeah, we had a monstrous flash-flood that flooded Metro Manila during Typhoon Ondoy. And what has just happened, under the same circumstances, can happen again… again, and again.
First published October 11, 2009