California Rainfall Deficit

Will the upcoming rainy season put a big dent into California’s precipitation deficits?

The answer is only with lots and lots of rain. As of the beginning of Sept, California is has 5-year rainfall deficits (starting in October 2011) of eight inches in the dryer southeast part of the state to almost fifty inches along the northern coast.  In the State of California, four year rain accumulations  (2011-2014) have been about 54-75% of average during that time. To put the shortfall into perspective, every region in the State is missing at least one years worth of rainfall. In fact, the southern coast of the State is missing about two year’s worth of rain (1.8 years to be precise). This shortfall isn’t so much of a hole as it is a giant canyon.

One yardstick used by the U.S. Drought Monitor group to declare drought is whether rainfall totals are in the lower 20 percent of the available record. For 5-year rainfall totals (October 2011 – September 2016) to get out of the lower 20% of records dating to 1928, precipitation totals from October 2015 to September 2016 must be higher than 135-160% of normal in the Northern part of the State , 160%+ of normal in the southeast to 198% of average in the San Joaquin Valley. This is a alot of rain/snow.