Explaining The California Drought (and Harsh Fire Season)

In 2013 State Climatologist Nicholas Bond of the University of Washington noted an unusual warming of the northeast North Pacific which during 2014-15 strengthened and did not weaken until 2016. The large area of warm water correlated to an upper level ridge pattern associated with the downstream polar vortex winter of 2013-14 and 2014-15 and was a major contributor to California drought. A weaker version of this phenomenon formed in 2017 southwest of California (Fig. 1) and has contributed to another drought and record 2017 fire damage.