Drought is defined as "a period of abnormally dry weather sufficiently prolonged for the lack of water to cause serious hydrologic imbalance in the affected area".  - Glossary of Meteorology (1959). In easier to understand terms, a drought is a period of unusually persistent dry weather that persists long enough to cause serious problems such a crop damage, extreme fire hazard, and/or water supply shortages. The severity of the drought depends upon the degree of moisture deficiency, the duration, and the size of the affected area. There is some disagreement over the causes of drought; theories include sunspots, climate change, volcanic dust, land alterations, ocean currents, and atmospheric pollutants. There are four different ways that drought can be defined. (1) Meteorological a measure of departure of precipitation from normal. Due to climatic differences, what might be considered a drought in one location of the country may not be a drought in another location. (2) Agricultural - refers to a situation where the amount of moisture in the soil no longer meets the needs of a particular crop. (3) Hydrological - occurs when surface and subsurface water supplies are below normal. (4) Socioeconomic - refers to the situation that occurs when physical water shortages begin to affect jobs, incomes, recreational capabilities and other such factors