Blue Oaks in California's San Joaquin Valley (IMAGE)
Caption
The annual tree rings on these blue oaks (Quercus douglasii) in California’s south Joaquin Valley show how much winter rain has fallen each year. The amount of winter rain in the valley is an indicator of how much winter precipitation falls in the Sierra Nevada mountains. By using tree-ring chronologies going back to 1405, a University of Arizona-led team of researchers figured out that snowpack in the Sierra Nevada in 2015 was at the lowest level in 500 years.
Credit
Kevin Anchukaitis
Usage Restrictions
This photo may only be used to illustrate a story about the research described in the news release, "Sierra Nevada Snowpack Lowest in Five Centuries." The photo credit must run with the picture.
License
Licensed content