Drought is a slow onset disaster and is caused by below normal rainfall over a prolonged period. Besides rainfall, other factors such as low soil moisture, irregular stream flow, less accessibility of groundwater or canal water supply and higher evapotranspiration (ET) increase the intensity of drought.
Droughts are recurring events that can disturb large areas, continuing for either a period of a few weeks or lasting up to several years. Drought affects vegetation, crops, livestock, humans, and eventually the economy.