NOAA/WDS Paleoclimatology - California and Western Nevada Precipitation Reconstruction for 1571-1977 AD

An analysis of the October 2013–September 2014 precipitation in the western United States and in particular over the California-Nevada region suggests this anomalously dry season, while extreme, is not unprecedented in comparison with the ~120-year long instrumental record of water year (WY, October–September) totals, and in comparison with a 407-year WY precipitation reconstruction back to 1571. Over this longer period nine other years are known or estimated to have been nearly as dry or drier than WY 2014. The three-year deficit for WY's 2012-2014, which in California exceeded the annual mean precipitation, is more extreme but also not unprecedented, occurring three other times over the past ~ 440 years in the reconstruction. WY precipitation has also been deficient on average for the past 14 years, and such a run of predominantly dry WY’s is also a rare occurrence in our merged reconstructed plus instrumental period record.