Canada Journal: The Sierra Nevada snowpack that is a critical water source for California fell to a 500-year low last winter far worse than scientists had estimated and underlining the severity of the current drought, according to new research.
For the study, published in the journal Nature Climate Change, researchers compared the snowpack on April 1 with estimates from the last 500 years derived from tree ring studies. Tree rings provide a window into the climate of centuries past, expanding during warm periods...