Weeks of pounding rain and snow have increased the Sierra Nevada snowpack -- a key source of water for California -- to 158 percent of normal, officials said Wednesday.
The weather situation was more dire to the north, however, as heavy rain and snow in the Sierra Nevada and rain in the San Francisco Bay Area continued to raise river levels and a weak tornado touched down early Wednesday near Sacramento.
According to the weather service, the tornado struck the community of South Natomas just after midnight and left a clear track of damage about a half-mile long in its wake. The twister shredded tree branches and dislodged a few awnings and shingles, forecasters said. No injuries were reported.
Thousands of people were forced to flee their homes because of flooding near rivers, and some homes were damaged. At least four deaths have been attributed to the storms.
The second of three successive storms expected to hit Southern California this week drenched Los Angeles early Wednesday.
Southern California forecasters predicted that Wednesday's storm would dump just a quarter-inch to three-quarters of an inch of rain in Los Angeles, posing little risk of mudslides in recent burn areas.
The rain caused a concrete patio at a home in the Hollywood Hills to teeter, prompting officials to close Laurel Canyon Boulevard at Kirkwood Drive.
A much colder storm expected to hit the area Thursday and Friday could cause larger problems, however. Weather service forecasters said that snow levels could drop to as low as 3,500 feet and that winter driving conditions could slow or stop traffic on Interstate 5 along the Grapevine and other mountain passes.
"That's not unusual for this time of year," said Tom Fisher, weather specialist for the National Weather Service in Oxnard. "This is more seasonal. What's happening in the Bay Area is unusual."
On Wednesday, Northern California was still reeling from a major storm that inundated rivers, flooded parts of Napa Valley wine country, and blanketed the frigid Sierra Nevada with heavy snow.