According to the National Climatic Data Center, of all the weather-related phenomena that are responsible for severe economic and environmental damage in the United States, droughts have historically had the greatest impact on the largest number of people. Droughts are more difficult to define as compared to hurricanes or tornadoes which are easily identified and straightforward to classify.
Drought can be defined in two ways, 1) a prolonged chronic shortage of water, as compared to the norm or 2) a period without precipitation during which the soil water content is reduced to such an extent that plants suffer from lack of water. Because dry conditions develop gradually and impact various regions differently, it is difficult to pinpoint when a drought begins or ends, or even to objectively assess its severity. However impacts of drought are not hard to predict or difficult to assess. Drought can reduce plant biomass and available forage. During severe or prolonged dry periods landowners must make difficult decision on how to manage these circumstances (i.e. destock or provide supplemental feed to their herds). An understanding of how to adapt ranch management during a drought may help with long term financial stability, herd health and plant and soil sustainability.
Short term drought
Short-term drought can impact decisions made for a particular year, such as whether there has been enough moisture to refill a reservoir or provide vegetation needed spring moisture to grow. The Palmer Drought Severity Index is probably one of the most widely used schemes for classifying droughts. It combines temperature, precipitation, evaporation, transpiration, soil runoff and soil recharge data for a given region to produce a single negative number representing conditions there. This index provides an estimate of soils moisture deficiency, which roughly correlates with a drought’s severity, and thus, its impacts.
Although droughts have been cited as a curse of humankind since biblical times, probably the most devastating drought on record was the dust bowl that occurred in the 1930s. According to the National Climatic Data Center, that drought affected almost the entire Plains region covering more than 60 percent of the country at its peak in July 1934. Long-term droughts can have serious economic and societal impacts.
An area can be impacted by short-term droughts and not necessarily experience a prolonged drought situation. However, in either case, it is wise for all landowners to have a drought contingency plan in place prior to a drought occurring.