2015-09-14. An Epic, 500-Year Snow Fail in California’s Iconic Mountains.

posted Sep 18, 2015, 3:02 PM by Alan Gould
By Cheryl Katz, National Geographic. For GSS Climate Change chapter 8. Excerpt: This year’s snowpack is the driest it’s been in at least 500 years, according to new research published Monday. This stark finding comes from an analysis of more than 1,500 California blue oak tree rings dating back to the early 1500s, when Spanish explorers were just beginning their conquest of the state. ...“What happened in 2015 is that very low precipitation co-occurred with record high temperatures. And that’s what made this snowpack low so extremely low,” says Valerie Trouet, a tree-ring research specialist at the University of Arizona in Tucson and co-author of the study published in Nature Climate Change. ...The 2015 Sierra snow water equivalent, a measure of water content, was just 5 percent of average over the past half-millennium, the researchers found. The next-closest lows were 2014 and 1977; both years the water content was 25 percent of average. ...The researchers had expected the 2015 results to be bad, “but we didn’t expect it to be this bad,” Trouet says. In fact, the water content of the Sierra Nevada snowpack could actually be at its lowest in 3,100 years, she said, based on a different analysis also reported in the study....  http://news.nationalgeographic.com/2015/09/15914-Sierra-California-snowpack-mountains-drought-centuries/