Winter storms have blanketed California's Sierra Nevada in snow, but the drought-prone state is still off to another drier-than-normal start to the crucial wet season, state officials said Thursday.

California water managers said Thursday the Sierra snowpack is only 67 percent of normal in this winter's first manual measurement. The amount of snow is measured monthly through the winter at more than 260 locations to help water managers plan for how much they can deliver to customers later in the year.

As snow in the Sierra melts in the spring and summer, it flows into reservoirs for storage and provides drinking and agricultural water for much of California. The snowpack supplies about 30 percent of the state's water needs, according to the Water Resources department.

Precipitation has bounced up and down as the state continues to recover from a devastating drought that led to tight water restrictions for residents and farmers. Persistent drought has also dried out trees and brush, contributing to severe wildfires.

Gov. Jerry Brown declared a formal end to a three-year drought emergency in 2017, but said water conservation efforts must continue.

"The last few years have shown how variable California's climate truly is and what a profound impact climate change has on our water resources," Karla Nemeth, director of the California Department of Water Resources, said in a statement.

More than 92 percent of California is considered abnormally dry, or in moderate, severe or extreme drought, according to the U.S. Drought Monitor, a project of several federal agencies and University of Nebraska-Lincoln. That's up from 56 percent a year ago.

California typically gets about two-thirds of its annual rainfall between December and March.

A storm is expected to drop snow and rain on much of Northern California, including the Sierra, this weekend and into next week, the National Weather Service said Thursday.

At Phillips Station, a water measurement site near Lake Tahoe, officials on Thursday measured 25.5 inches (65 centimeters) of snow and a snow water equivalent of 9 inches (23 centimeters) — about 80 percent of average for the early January survey.

"We still have three wet season months ahead of us, so there's time for the snowpack to build and improve before it begins to melt, which usually starts happening around April 1," Michael Anderson, climatologist for the water department, said in a statement.