The first manual snow survey of the 2018 revealed very little snowpack in the Sierra Nevada — not surprising as the state has seen very little precipitation this winter season.
The Department of Water Resources’ measurements at Phillips Station revealed a snow water equivalent of 0.4 inches, only 3 percent of the early-January average of 11.3 inches.
“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.”
The measurements taken on Wednesday indicate the SWE of the northern Sierra snowpack is 2.3 inches, 21 percent of the multi-decade average for the date. The central and southern Sierra readings were 3.3 inches (29 percent of average) and 1.8 inches 20 percent of average) respectively. Statewide, the snowpack’s SWE was 2.6 inches, or 24 percent of the Jan. 3 average.
“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 belowground storage, and improving our infrastructure to protect our clean water supplies against disruptions.”
In January 2017, coming off a six-year drought, the snow water equivalent was 6 inches, 53 percent of the early-January average. The area then went on to record the wettest winter in history.
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, 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.
California traditionally receives about half of its annual precipitation during December, January and February, with the bulk of this precipitation coming from atmospheric rivers. 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. Davis noted that forecasting accuracy falls off dramatically after just a week or 10 days into the future.
“Current technology and computer modeling can tell us what our weather might be weeks into the future, but we’re essentially blind to what the weather will be beyond the two-week mark,” he said. “That’s why we are putting in so much effort to improving medium- and long-range modeling.”
Rainfall is in Turlock’s future, according to the National Weather Service. Rain is forecast in the Turlock area on Saturday, with a break on Sunday, before returning on Monday and Tuesday.