Natural cycles, sea surface temperatures found to be main drivers in ongoing event
According to a new NOAA-sponsored study, natural oceanic and atmospheric patterns are the primary drivers behind California's ongoing drought. A high pressure ridge off the West Coast (typical of historic droughts) prevailed for three winters, blocking important wet season storms, with ocean surface temperature patterns making such a ridge much more likely. Typically, the winter season in California provides the state with a majority of its annual snow and rainfall that replenish water supplies for communities and ecosystems.
![The Enterprise Bridge passes over a section of Lake Oroville that was nearly dry on September 30, 2014, in Oroville, California. Lake Oroville, California's 2nd largest reservoir, was at 49% of average (30% of capacity), the second lowest level on record (behind 1977.) Heavy rains in December 2014 allowed lake levels to recover slightly--as of January 23, 2015 Lake Oroville was at its 7th lowest level of the past 35 years. (Image credit: Andrew Innerarity/California Department of Water Resources) The Enterprise Bridge passes over a section of Lake Oroville that was nearly dry on September 30, 2014, in Oroville, California. Lake Oroville, California's 2nd largest reservoir, was at 49% of average (30% of capacity), the second lowest level on record (behind 1977.) Heavy rains in December 2014 allowed lake levels to recover slightly--as of January 23, 2015 Lake Oroville was at its 7th lowest level of the past 35 years.](/sites/default/files/styles/landscape_width_1275/public/legacy/image/2019/Jun/PHOTO-drought-oroville-sep2014-010616-750x516-landscape.jpg?h=6a103a14&itok=Qg0Fqxwv)
The Enterprise Bridge passes over a section of Lake Oroville that was nearly dry on September 30, 2014, in Oroville, California. Lake Oroville, California's 2nd largest reservoir, was at 49% of average (30% of capacity), the second lowest level on record (behind 1977.) Heavy rains in December 2014 allowed lake levels to recover slightly--as of January 23, 2015 Lake Oroville was at its 7th lowest level of the past 35 years. (Image credit: Andrew Innerarity/California Department of Water Resources)