Does Sierra snowfall promise end to drought?

In this April 2015 file photo, Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, checks the depth of the snow pack.

In this April 2015 file photo, Frank Gehrke, chief of the California Cooperative Snow Surveys Program for the Department of Water Resources, checks the depth of the snow pack. Photo: Rich Pedroncelli, Associated Press Photo: Rich Pedroncelli, Associated Press Image 1 of / 15 Caption Close Does Sierra snowfall promise end to drought? 1 / 15 Back to Gallery

The snow numbers, and what they mean for California, are on a trajectory that shows this winter could be a drought-breaker.

The intuitive feeling across the board, with all the ski and snowboard parks in California open for the Christmas holidays, is that the winter is off to a big start. The numbers bear that out, said Michael Pechner of Golden West Meteorology.

For comparisons, the best site is the Central Sierra Snow Lab Weather Station in Norden (Nevada County), built in 1946 and operated by UC Berkeley. It is located near Historic Route 40, just off Interstate 80 near Donner Summit west of Truckee.

Last year on this date, Norden had 19 inches of snow on the ground, and had received a season total snowfall of 66 inches, Pechner said.

Video: Sierra sees heavy snow, rain in Christmas week storm

In comparison, Norden now has 62 inches on the ground and a seasonal total snowfall of 130 inches.

The 130-inch snowfall to date is only 33 inches less than last winter’s season total.

The normal snow numbers at Norden for Christmas is 42 inches on the ground (20 fewer inches than now) and 112 inches of snow for the season (18 fewer than now), Pechner said.

One-third of California’s water comes from the snowpack in the Sierra Nevada. A big snowpack, of course, means all the ski parks are open and drives the winter recreation-based economy. Melting snow is what fills most reservoirs and drives the lake-based summer season for camping, boating and fishing.

At Donner Pass near Norden, anybody who drove I-80 last year to north Tahoe will never forget the sight: Bare dirt along the highway. Warm temperatures and high snow levels meant rain, not snow. At the Blue Canyon weather station near Nyack (Placer County), located at 5,280 feet along I-80, the gauge measured 57 inches of rain last winter instead of the 252 inches of snow it gets as an average.

As the snow piles up in the high country, the reservoirs that depend on snowmelt to fill won’t climb significantly until spring. One to watch is Shasta, the state’s largest reservoir, which gets most of its water from rain, not snow, and is 31 percent full and starting to climb.

Tom Stienstra is The Chronicle’s outdoor writer. Twitter at: @StienstraTom. E-mail at tstienstra@sfchronicle.com.