Drought refers to a lack of precipitation over an extended time period. Droughts can be meteorological, agricultural, hydrological, or socioeconomical . Meteorological drought refers to dry conditions related to climate. Agricultural drought refers to factors related to irrigation and soil moisture. These are interconnected with precipitation, evapotranspiration, groundwater tables, and reservoir levels.
Hydrological drought refers to a lack in water supplies, often evaluated at the watershed scale.
Socioeconomic drought refers to the impacts on humans due to meteorological, agricultural, and hydrological droughts. It can affect the exchange of goods and services, and can reshape consumer habits and even cultural norms. Impacts from all four categories are interconnected. Without a doubt, any type of drought will somehow have an affect on our daily lives. The Drought Monitor is based upon six national indices that measure national preliminary precip data, soil moisture models, daily streamflows, percent normal precipitation, topsoil moisture, and vegetation health via satellite.