Characterizing the extreme 2015 snowpack deficit in the Sierra Nevada (USA) and the implications for drought recovery

• Published in: Geophysical research letters Vol. 43; no. 12; pp. 6341 - 6349
• Main Authors: Margulis, Steven A., Cortés, Gonzalo, Girotto, Manuela, Huning, Laurie S., Li, Dongyue, Durand, Michael
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.06.2016; Wiley
• Subjects: Computer simulation; Confidence intervals; Data; Drought; Droughts; El Nino; El Nino phenomena; Elevation; Extreme weather; Meteorology; Monte Carlo simulation; Recovery; Simulation; Snow; Snow accumulation; Snowpack; Statistical methods; water supply; United States > US; Sierra Nevada Mountain Range; USA, California, Sierra Nevada Mts
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL068520

Analysis of the Sierra Nevada (USA) snowpack using a new spatially distributed snow reanalysis data set, in combination with longer term in situ data, indicates that water year 2015 was a truly extreme (dry) year. The range‐wide peak snow volume was characterized by a return period of over 600 years (95% confidence interval between 100 and 4400 years) having a strong elevational gradient with a return period at lower elevations over an order of magnitude larger than those at higher elevations. The 2015 conditions, occurring on top of three previous drought years, led to an accumulated (multiyear) snowpack deficit of ~ −22 km3, the highest over the 65 years analyzed. Early estimates based on 1 April snow course data indicate that the snowpack drought deficit will not be overcome in 2016, despite historically strong El Niño conditions. Results based on a probabilistic Monte Carlo simulation show that recovery from the snowpack drought will likely take about 4 years. Key Points The 2015 Sierra Nevada range‐wide snow volume was characterized by a return period of over 600 years with a strong elevational gradient The accumulated snowpack drought deficit volume ending in 2015 was the largest over the 65 year record analyzed Despite historically strong 2016 El Nino conditions, it is highly likely that recovery to predrought conditions will take about 4 years