Arizona researchers have found evidence of a historical drought in southern California trees, and the plants can tell water managers how to prepare for the future.
The California Department of Water Resources commissioned a study from the University of Arizona to look at tree rings over centuries.
Those tree rings showed two to three years of dry conditions are common in the Golden State.
However, the period of 2012 to 2016 was, for a lot of southern California, the driest or second-driest five-year drought on record. Those records start in the 1400s.
State officials said this study helps show how local water managers better work with the future risk of dry conditions and water supply.
