Flash floods are dangerous because they are unpredictable and easily underestimated. Easily formed as a byproduct in a weather event, a water dam failure, human error in water control, seismic, or volcanic activities, flash floods hit hard and fast for a few hours and are over. However, the destruction left behind and the lives taken by negligence are serious matters.
The unpredictability of a flash flood is dangerous because they can’t be forecast until they happen or are close to happening, and by then it may be too late to issue a warning. For this reason if storms are thought to carry large quantities of water, national weather advisory bulletins will warn people of flash flood possibilities. When the cause is something other than rain alone, the probability of warning is almost completely impossible. The only hope is that people are knowledgeable of them when they happen, and are not underestimated.
Flash floods are easy to underestimate because the presence of water over a road or a swelling stream may not looking very deep, but can be swift enough to push a car off the road into deeper water, or stall it by getting into the engine. Stalled vehicles are then subjected to the full mercy of the rising waters, and are either swept downstream, or trap motorists in the rising waters with nowhere to go. People who think they can escape the flood by getting to shore are often swept away and drown. Other flash floods can kill livestock animals, pets, or raze even some structures.
With flashfloods, there is no size limit, and the largest of these types can destroy entire towns and communities if they are located in the path of a failed dam. Canyon deluges, tsunamis, and glacier melts initiated by volcanic heat release can all catch people completely unaware and devastate entire regions. Also, the likelihood of survival against the force in a flashflood is difficult if not fully protected from the debris it carries. Debris in the form of sticks, stones, trash, or even ice, is capable of inflicting far more damage upon a structure or person than just the water alone. Sometimes getting to high ground just isn’t enough to escape the force of the flood.
When the flash flood is over, it isn’t entirely so. Just like with other floods, there is a risk of contaminated ground waters from spilled chemicals, sewage, and biological agents. However, this risk isn’t as high as the saturation from a long lasting flood, but caution needs to be taken regardless.
