Droughts in California
The historical and ongoing periodic droughts in California result from various complex meteorological phenomena, some of which are not fully understood by scientists. Drought is generally defined as "a deficiency of precipitation over an extended period of time (usually a season or more), resulting in a water shortage." A lack of rainfall (or snowfall) or precipitation in meager quantities, higher than average temperatures and dry air masses in the atmosphere commonly underlie drought conditions; these natural factors are further complicated by increases in populations and water demands.