The storm that moved in Friday, powered by a warm, moisture-packed system from the Pacific Ocean known as a Pineapple Express, dropped more than 7 inches of rain on Marin County's Mt. Tamalpais, an average of 4 inches in Sonoma County and one to three inches in San Francisco, San Jose and other urban areas as of Saturday morning, National Weather Service hydrologist Mark Strudley said.
With areas north of San Francisco forecast to see another few inches by Sunday, the downpour, while ample enough to flood roadways and prompt warnings that parched streams could be deluged to the point of overflowing, by itself will not solve the state's drought worries, Strudley said.
"The yearly rainfall around here, depending on where you were, was less than 10 percent of normal," he said. "The additions from this last series of storms and the totals are taking a dent out of it, but it is not a significant dent."
The storm deposited a foot of snow of on the top of Lake Tahoe ski resorts that have relied on man-made snow for much of the season, and elevations above 7,500 feet were expected to get another foot or two by Sunday, said Holly Osborne, a National Weather Service meteorologist in Sacramento.
The additions, which followed some brief periods of snow in the last week, already have improved the outlook for the Sierra Nevada snowpack, which provides about a third of California's water supply. When state surveyors last checked on Jan. 30, the snow pack was at 12 percent of normal for this time of winter. By Saturday, it was at 17 percent of normal.
"At least we are getting something versus nothing," Osborne said.
While the fresh snow delighted skiers and resort operators, the Sierra Avalanche Center warned Saturday that the danger of avalanches, both natural and human-triggered, was high in a wide swath of the Central Sierra Nevada because wind had blown new snow onto weak layers of existing ice and rock.
Tiffany Morrissey, a Silicon Valley family doctor who was working on ski patrol at the Alpine Meadows resort Saturday, said several lifts and runs were closed as a safety precaution but that cars carrying people wanting a taste of fresh powder filled up the parking lots.
"It's a heavy, wet snow, and because of the avalanche danger the lines are pretty long. But you could hear people having a great time out on the mountain," Morrissey said.
Forecasters hope the storm portends an end to the persistent dry weather that has plagued the state for months and contributed to its drought emergency. Light precipitation is forecast for Wednesday and Thursday, and another storm is possible next weekend.
Southern California was expected to be mostly dry. Forecasters said measureable rain over the weekend likely would not fall farther south than San Luis Obispo and northern Santa Barbara counties as a ridge of high pressure pushes up from the south.
The same subtropical weather system marinating Northern California also brought a third straight day of unsettled weather to Oregon, where the powerful storm caused snow to fall in and around Portland, scattered power outages and ice-storm warnings
The National Weather Service said the Portland area should expect another 4 to 8 inches of snow through Saturday night and the Columbia River Gorge might get more. Meanwhile, freezing rain was expected in the wine country southwest of Portland to the lower Willamette Valley south of Eugene, triggering an ice-storm warning for a stretch of more than 100 miles.
"Snow is bad. But ice is worse," Miles Higa, a National Weather Service meteorologist, said.
More than 3,000 people in the Portland region were without power Saturday morning, but most had the lights back before noon.
Despite its northern location on the U.S. map, Portland sometimes goes an entire winter without snow, and residents and businesses are not prepared to shovel their sidewalks. The Portland Art Museum, Multnomah County Library and many shops were closed.
For bicyclists, the weather even doomed the annual "Worst Day of the Year Ride." Organizers had hoped to stage a 15-mile ride through downtown Portland after announcing Thursday that its more challenging 46-mile event through the hills of west Portland was canceled for safety reasons.
"Alas, Mother Nature wins this round," organizers announced on the event's website Saturday.