Sierra Nevada Snowpack at 500-Year Low

According to a study from the University of Arizona, the Sierra Nevada snowpack is currently at a 500-year low. Bare ground in places usually covered in feet of ice led California Governor Jerry Brown to declare mandatory water restrictions in April.

Because "the state witnesses roughly 80 percent of its precipitation in the winter months [...] Winters that yield less snow mean there's even less water for the state to use during summer, as melting snow is supposed to restock the state's reservoirs and aqueducts."

"The university says its research is the first of its kind to compare the 2015 snowpack with levels across five centuries. This was accomplished by examining tree-ring data that showed annual winter precipitation in central California from 1405 to 2005."