A new report led by University of Arizona researchers compares the 2015 snowpack in the Sierra Nevada mountains in California with levels for the past 500 years and finds that it is the lowest in that time.
“Our study really points to the extreme character of the 2014-15 winter. This is not just unprecedented over 80 years – it’s unprecedented over 500 years,” said Valerie Trouet, an associate professor of dendrochronology at the UA Laboratory of Tree-Ring Research.
“We should be prepared for this type of snow drought to occur much more frequently because of rising temperatures,” Trouet said.
“Anthropogenic warming is making the drought more severe.”
California’s current record-setting drought began in 2012 and the lack of snow in 2015 stems from extremely low winter precipitation combined with record high temperatures in California in January, February and March, Trouet said.
The result is a disaster for California, which sees 80% of its precipitation in winter. Snowpack level is generally measured on 1 April each year, a time when the snowpack is at its peak.
“Snow is a natural storage system,” she said. “In a summer-dry climate such as California, it’s important that you can store water and access it in the summer when there’s no precipitation.”