Flash floods are incidences of rapid flooding in which low-lying areas are completely submerged. In many instances, one occurs as the result of some type of natural phenomena like heavy rains, hurricanes, or some type of tropical storm. A flash flood may also occur due to the collapse of a natural or man-made dam, however. There is usually very little advance warning that a given area will flood, making it somewhat difficult for people living in the affected area to determine whether or not to seek higher ground.
When this type of flood takes place due to natural phenomena, the process often begins with the ground becoming so saturated with rainfall that it is unable to absorb all the water that has fallen in a short period of time. Since water will run downhill, it will tend to collect in low-lying areas. If the rain or other weather condition does not abate, the water level will rise, eventually covering the area completely. Any homes or other structures in the area are flooded and likely to sustain damage.
When the flash flood is cause by the collapse of a natural or man-made dam, there may be no advance notice to warn people to leave the area. Because of its rapid discharge, the water has a tremendous ability to not only damage but to completely destroy anything in its path. Entire towns have been destroyed due to the collapse of a dam, leaving little behind but building foundations and the accumulated rubble from upstream sources.
A sudden flood that completely engulfs an area is sometimes referred to as a super soaker flash flood. This type of flooding activity is likely to completely cover entire structures; depending on the water current, the water in the flooded area may be relatively calm and begin to subside after the rain stops. If there is a strong downstream current, however, the soaker flood may uproot trees as well as buildings, and move them miles away from their original location.
In order to minimize the loss of life that can come with a flash flood, many communities have implemented some type of early warning system. In the event that there is a strong suspicion that heavy rain will cause low lying areas to flood, people may be urged to leave the area until it is determined that it will not be subject to flooding. Warning systems to alert people that a dam has collapsed are also common to many municipalities. It is not unusual for escape routes to be pre-planned, allowing people to know which roads to take and which direction to travel in order to get out of the way of the impending flood in the most efficient manner.
