|Understanding floods and how to remain safe|
After last week’s heavy rains, we are reminded that we are prone to flooding in the TCI.
Although flooding is associated with hurricane weather, even a light rain shower can cause large puddles of water on the roads. Be prepared for flooding by understanding its nature and what you can do to avoid flood waters.
There is one rule that governs floods: Water will always run downhill. Low lying areas are at higher risk of flooding than higher areas, but any area which allows for pooling of water can cause flood damage.
The severity of a flood depends not only on the amount of water that accumulates in a period of time, but also on the land’s ability to deal with this water. When it rains, soil acts as a sort of sponge. When the land is saturated — that is, has soaked up all the water it can — any more water that accumulates must flow as runoff.
Some materials become saturated much more quickly than others. To see how this works, just take a bucket of water outside and try wetting various surfaces. Soil is an excellent sponge. In most cases, you can dump several buckets of water on it and it will soak the water right up. Unfortunately, soil in the TCI is not so prevalent, but rock is.
Rock is not so absorbent — it doesn’t seem to soak up any water at all. Hard clay falls somewhere in between. Generally, soil that has been tilled for crops is less absorbent than uncultivated land. One of the least absorbent surfaces is concrete, which is why roads and parking lots tend to flood, especially those that do not have a proper run off area.
The worst damage from floods, the loss of life and homes is caused primarily by the sheer force of flowing water. In a flood, two feet (61 cm) of water can move with enough force to wash a car away, and 6 inches (15 cm) of water can knock you off your feet. It may seem surprising that water, even a lot of water, can pack such a wallop. After all, you can peacefully swim in the ocean without being knocked around, and that’s a massive amount of moving water. So why do flood waters behave differently?
Flood waters are more dangerous because they can apply much more pressure than a calm sea. This is due to the massive differences in water volume that exist during many floods. In a flood, a lot of water may collect in an area while there is hardly any water in another area. Water is fairly heavy, so it moves very quickly to “find its own level.” The bigger the difference between water volumes across an area, the greater the force of movement. But at a particular point, the water doesn’t look so deep, and so doesn’t seem particularly dangerous — until it’s too late.
Nearly half of all flood deaths result from people attempting to drive their cars through rushing water.