Drought planning and preparation should be a priority for most ranching operations, as ranches are likely to be located in areas of natural grassland and one of the formative factors for grasslands is erratic moisture availability. Drought is not just dry weather; drought occurs when there is a significant reduction in normal precipitation. A desert area that received only 9 inches of rain is dry, but it is not in drought unless annual precipitation falls well below 9 inches; an area that is in a 40-inch rainfall belt and received 20 inches is in a serious drought.
Our home ranch in Nolan County, Texas, was in a 20-inch rainfall area that was very drought-prone; local wags said that the 20-inch average came about because it would rain 60 inches one year and then skip two years.
Where moisture availability is constant, the vegetation tends to be made up of longer-lived plants (trees). If drought kills most of the local vegetation, grasses and forbs can germinate from seed and reproduce quickly, but trees require much more time to reach maturity. The fantastic ryegrass and clover pastures of England and Ireland did not come into being until the oak forests that were originally there disappeared into ship timbers and charcoal kilns. If humans were removed from these areas, the oak forests would return because of the uniformity of the local moisture patterns.
The frequency and severity of droughts vary widely according to location; knowing the probability of drought in the local environment is essential information for formulating drought planning management strategies. Equally important is recognizing the early signs of impending drought — the sooner drought is recognized, the more effectively its effects can be offset. If drought is recognized as a normal occurrence, and it is, then plans can be made to reduce its impact upon the operation and upon the soil-plant-animal complex on which the operation depends.
The National Weather Service keeps detailed weather records for many places in the United States, and an examination of these records for your area is a good place to start in determining the likelihood of drought and need for drought planning. There is nothing you can do to keep drought from occurring, but you can do a great deal to reduce its impacts.