Flash Flooding – The Causes and Effects
Flooding is the single most common natural disaster in the United States, occurring year round n all fifty states, and for a variety of reasons. In many cases flooding may be predicted and planned for due to heavier than average rainfall over a given area during a specific time frame. Lakes, rivers, and streams may slowly rise and overflow their banks over a period of several days, allowing nearby homeowners to properly prepare and or evacuate before flood waters become a problem.
Flash floods are a whole nother problem altogether….since they are rapidly forming flood conditions, occurring over a period of minutes or hours as opposed to days, and offering virtually no warning to those who may be caught in their path. Flash floods are commonly associated with tropical storms and hurricanes, as well as melting ice or snow. Most of these floods form within six hours and are perfectly capable of washing away property and lives with ease.
Flooding occurs when the ground becomes saturated, unable to hold any more water. The excess will build up and flow in the path of least resistance. Depending on how fast the ground reaches its limit, the flood problem develops.
The National Weather Service suggests “Turn Around, Don’t Drown” when it comes to dealing with flash flooding. Flash floods can literally wash away roads, and what looks like a shallow stream across a roadway may effectively mask the fact that there is no longer a road there. Most flood related fatalities occur as a result of people becoming trapped in their vehicles and being swept away by flood waters. The inherent danger of flash floods lies in their sudden nature and fast moving water. It only takes about six inches of water to knock a grown man off his feet, and about two feet of water can float a full sized car. More people are killed by flash floods every year than are killed by tornadoes, lightning, or hurricanes.
Flash floods produce fast moving water than can sweep away structures if there is enough power behind it. For this reason alone it is important to heed flash flood warnings, which means that such a flood is imminent. You may only have a matter of minutes to save your life and the lives of your family. You should immediately seek higher ground and abandon any vehicles you are in.
Avoid creeks and rivers, as well as canyons and gullies, when flash flood conditions are present. If a flash flood occurs in a canyon, you will have nowhere to evacuate to. Always be aware of rapidly changing weather conditions and be ready to evacuate promptly when the weather turns malevolent.