On January 3 the Department of Water Resources (DWR) performed the first snow survey for 2018 about 90 miles east of Sacramento at Phillips Station in the Sierra Nevada. The readings found little snowpack, which was expected after a dry December throughout the state.
Measurements revealed a snow water equivalent (SWE) of 0.4 inches, which is only 3 percent of the average. Since 1964 the historic SWE average at Phillips Station has been 11.3 inches in early January. Electronic readings from DWR’s 103 stations located throughout the Sierra Nevada also indicated the SWE of the northern Sierra snowpack is 2.3 inches, which is 21 percent of the multi-decade average. California’s overall snowpack SWE was measured at 2.6 inches, roughly 24 percent of the average for this time of year. SWE is the depth of water that would potentially result if the entire snowpack melted at once.
“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 the snow survey at Phillips. “There’s plenty of time left in the traditional wet season to reverse the dry trend we’ve been experiencing.”
California typically receives approximately half of its annual precipitation during the months of December, January, and February. The majority of precipitation comes from atmospheric rivers (ARs). An atmospheric high-pressure zone spanning the western United States has consistently been prohibiting ARs from getting to California this winter. The state still has a chance for significant rainfall and snow this winter if the zone were to dissipate or move.
The snowpack typically supplies approximately 30 percent of the water needs of California. The more significant of snowpack creates the better potential for reservoirs to receive the necessary runoff as it melts in the spring and early summer.
The DWR website has the results of the snow survey available for review.