California seems to be in the news a lot lately when it comes to flooding, earthquakes, and wildfires but it has turned many away from the fact that the historic California drought of the past few years is the worst one that has occurred in the last 500 years, according to a recent study published in the journal Nature. After the announcement by California state officials that they had found no snow in the Sierra Nevada mountains for the first time in the 75 years since snowfall records began, a research team conducted a study aimed at finding out more about the region’s long-term snowfall history. By studying the thickness of rings in core samples taken from blue oak trees growing in the mountains, the researchers were able to accurately measure the winter rainfall records during past centuries.

Their findings came as a surprise. It was already known that the current drought cycle had broken records, but no one suspected that so much time had passed since the last dry period of this magnitude. The four-year drought has forced the state to begin issuing mandatory water cuts in many areas. Some municipalities have been ordered to cut their water usage by as much as 35 percent as reservoirs and groundwater supplies are being drained without being replenished. The annual snowpack melt supplies up to 30 percent of California’s water supply. In the past few years, however, the amount of accumulated snow has been so diminished that reservoirs, lakes, rivers and other bodies of water fed by the runoff are nearing record low levels. FULL REPORT