Newsweek provided this rather depressing story about the historically low Sierra snowpack.
From the magazine:
In April this year, the annual measurement of the Sierra Nevada mountains’ snowpack in California brought startling results: There was no snow at all. For nearly three-quarters of a century, the average depth of snow in the measurement spot at Phillips Station, about 90 miles east of Sacramento, had been 66.5 inches. A new report published online Monday in Nature Climate Change finds that the snowpack level in 2015 was the lowest in five centuries.
“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,” Valerie Trouet, an associate professor of dendrochronology at the University of Arizona’s Laboratory of Tree-Ring Research, says in the university’s press release.
The snowpack, which is usually at its peak at the start of April, is an accumulation of winter precipitation that slowly melts during warmer months to replenish streams, lakes, groundwater and reservoirs. According to the University of Arizona report, California gets 80 percent of its precipitation during the winter, and the snowpack accounts for 30 percent of its water supply.
“Snow is a natural storage system,” Trouet 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.” This year’s low was the result of scant winter precipitation and high temperatures between January and March. The drought that began in California in 2012 has been called the worst in over a millennium, and researchers have predicted that the future holds even more severe “megadroughts.”