Causes of the 2011-15 California drought

Richard Seager, Lamont-Doherty Earth Observatory, Palisades, United States, Martin P Hoerling, NOAA Boulder, ESRL, Boulder, CO, United States, Siegfried D Schubert, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Hailan Wang, SSAI, Hampton, VA, United States, Bradfield Lyon, International Research Institute for Climate and Society, Columbia University, Palisades, NY, United States, Arun Kumar, NOAA/NCEP, Climate Prediction Center, College Park, MD, United States, Jennifer Nakamura, Lamont Doherty Earth Obs, Palisades, NY, United States and Naomi Henderson, Lamont -Doherty Earth Observatory, Palisades, NY, United States