The Sierra Nevada snowpack — the source of roughly a third of California’s water supply — remains nearly 30 percent below average for this time of the year despite the state recently witnessing its heaviest rainfall in decades. In an update released Tuesday, California’s Department of Water Resources (DWR) said that the snowpack currently has a water content of 10.5 inches, just 72 percent of the Dec. 27 average. “It’s too soon to know whether this winter’s wet season will deliver enough rain and snow to move California closer to the end of the state’s five-year drought,” the DWR said.