In 119 years of recorded history, 2013 was the driest calendar year for the state of California. On January 17, 2014 California State Governor, Jerry Brown, declared a drought state of emergency.
Snowpack, through runoff, provides about one-third of the water used by California's cities and farms. On May 1, 2014, the Department of Water Resources released their final Snow Survey of the year results stating that the statewide snowpack's water content is at 18% of average for the date. As of December 8, 2014, the California Department of Water Resources measured the statewide water content of snowpack at only 7% of the average historical April 1 snowpack measurement - crucial because this is when the snowpack is normally at its peak and begins to melt into streams and reservoirs.
Closely monitoring the effects of, and studying the current drought in the context of long-term hydrologic, climatic, and environmental changes, is essential for successful science-based planning and preparedness for future droughts.
A drought is a period of drier-than-normal conditions that results in water-related problems. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought.
The term "drought" can have different meanings to different people, depending on how a water deficiency affects them. Droughts have been classified into different types such as:
- meteorological drought - lack of precipitation
- agricultural drought - lack of soil moisture, or
- hydrologic drought -reduced streamflow or groundwater levels
It is not unusual for a given period of water deficiency to represent a more severe drought of one type than another type. For example, a prolonged dry period during the summer may substantially lower the yield of crops due to a shortage of soil moisture in the plant root zone but have little effect on groundwater storage replenished the previous spring.