Drought is a hazard of nature. We can’t see it ignite, like a fire, or predict where it is likely to touch down, as we do a tornado. Like its natural hazard cousins, however, drought can leave a trail of destruction that may even include loss of life.
And while we might refer to a fire’s crackle or the roar of a tornado, a drought hazard does not announce its arrival. In fact, those familiar with drought call it a “creeping phenomenon,” because what may first appear to be merely a dry spell can only be discerned in hindsight as the early days of a drought.
Drought’s stealthy reputation is also based on the way its effects vary from region to region. A week without rain might be considered a drought in a tropical climate like Bali, while a gap of only seven days between rains might be unusual in Libya, a desert area where annual rainfall is less than seven inches(180 millimeters).
In the most general sense, drought is defined as a deficiency of precipitation over an extended period of time(usually a season or more), resulting in a water shortage. The effects of this deficiency are often called drought impacts. Natural impacts of drought can be made even worse by the demand that humans place on a water supply.