SAN FRANCISCO — Californians accustomed to complaining about the slightest change in the weather welcomed a robust weekend storm that soaked the northern half of the drought-stricken state Saturday even as rain and snow brought the threat of avalanches, flooding and rock slides.
The storm that moved in Friday, powered by a warm, moisture-packed system from the Pacific Ocean known as a Pineapple Express, had 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, National Weather Service hydrologist Mark Strudley said.
With areas north of San Francisco forecast to see another few inches by Sunday, the downpour was ample enough to flood roadways and prompt warnings that parched streams could be deluged to the point of overflowing, but 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.”
Still, seeing the water levels in a local reservoir and his backyard pond creeping up and small streams flowing again cheered Willits City Councilman Bruce Barton. Willits, a city in the heart of redwood country that usually sees about 50 inches of rain a year and was expected to get about four inches over the weekend, is one of 17 rural communities that California’s Department of Public Health recently described as dangerously low on water.
“It’s guarded optimism. We are a long ways from where we need to be, but we have to start with some sort of a raindrop,” Barton said.
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.
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.
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.