Written by Gabriel Dillard
As predicted, the Sierra Nevada is feeling a little dry this season thanks to scarce rain and snow fall, according to the state’s Department of Water Resources.
The season’s first snow survey was taken at Phillips Station east of Sacramento, and found a snow water equivalent (SWE) of 0.4 inches, or 3 percent of the average SWE of 11.3 inches in early January, calculated since 1964.
SWE is defined as the depth of water that theoretically would result if the entire snowpack melted instantaneously.
“As we’re only a third of the way through California’s three wettest months, it’s far too early to draw any conclusions about what kind of season we’ll have this year,” DWR Director Grant Davis said. “California’s great weather variability means we can go straight from a dry year to a wet year and back again to dry. That’s why California is focusing on adopting water conservation as a way of life, investing in above- and below- ground storage, and improving our infrastructure to protect our clean water supplies against disruptions.”
The Department of Water Resources also takes electronic readings from 103 monitoring stations scattered throughout the Sierras. Those found that northern Sierra snowpack is at 2.3 inches, or 21 percent of average. The central Sierra reading was 3.3 inches, or 29 percent of average, while the southern Sierra has 1.8 inches, or 20 percent of average.
Collectively, the state’s snowpack is at 2.6 inches, or 24 percent of average.
“The survey is a disappointing start of the year, but it’s far too early to draw conclusions about what kind of a wet season we’ll have this year,” said Frank Gehrke, chief of the California Cooperative Snow Surveys Program who conducted today’s survey at Phillips. “There’s plenty of time left in the traditional wet season to reverse the dry trend we’ve been experiencing.”
California traditionally receives about half of its annual precipitation during December, January, and February, with the bulk of this precipitation coming from atmospheric rivers (ARs). So far this winter, an atmospheric high-pressure zone spanning the western United States has persistently blocked ARs from reaching the state. If that zone were to move or break up, storms could deliver considerable rainfall and snow this winter.
California’s exceptionally high precipitation last winter and spring has resulted in above-average storage in 154 reservoirs tracked by the Department. DWR estimates total storage in those reservoirs at the end of December amounted to 24.1 million acre feet (MAF), or 110 percent of the 21.9 MAF average for the end of the year. One year ago, those reservoirs held 21.2 million acre-feet (MAF), 97 percent of average. End-of-year storage is now the highest since December 2012 (24.3 MAF), which was early in the first of five consecutive water years of drought in California.