Rounds 1 and 2 in this wet and windy week may not have been as bruising as people expected. But weather forecasters say Northern California should keep its guard up for Round 3 arriving tonight.
The weather today is expected to be unsettled, with sporadic rain shower activity but no widespread downpours. Officials said this will give rivers and creeks a chance to recover from Friday's heavy rainfall.
"Saturday's going to be a break, and we don't want people to relax," said Rob Hartman, hydrologist in charge of the California-Nevada River Forecast Center, a branch of the National Weather Service based in Sacramento. "Because Sunday's going to be a stemwinder."
The heaviest rain and winds of the week are expected to begin tonight and continue through Sunday morning. Rainfall amounts during this period may exceed those already delivered in the first two storms.
Sacramento may see as much as 3 inches of additional rain through Sunday, compared with 1.3 inches recorded between Wednesday and Friday, according to the National Weather Service. Blue Canyon along Interstate 80 in the Sierra Nevada may see 9.7 inches of rain, compared with 4.1 inches in the first two storms.
"The heavy stuff looks like late Saturday night," said George Cline, a National Weather Service forecaster in Sacramento. "And Sunday's looking really wet."
Friday's storm did not produce quite as much rainfall as initially predicted, which reduced the flood threat in some places, particularly on the upper Sacramento River in Tehama County.
Still, the storm still brought its share of mayhem.
Early Friday morning, a Pacific Gas and Electric Co. worker was killed when his repair truck crashed into a traffic signal pole in West Sacramento.
The storm also contributed to a major accident on Interstate 5 during the Friday morning commute in Sacramento. A big rig jackknifed near Sutterville Road, crashing through the center barrier and blocking one traffic lane in each direction.
Several mudslides were reported, including one that briefly closed Highway 16 near Rumsey in Yolo County Friday morning. Another mudslide closed portions of Highway 84 in Fremont.
Numerous brief power outages also struck the state. The most notable occurred Friday morning when lights illuminating the San Francisco-Oakland Bay Bridge suspension span went dark.
Localized flooding and the potential for mudslides are particular concerns in Shasta and Tehama counties, which saw some of the state's most intense rainfall on Friday.
Officials from the U.S. Forest Service and the California Department of Forestry and Fire Protection were watching closely in case of mudslides on forested areas that burned in August wildfires. Risky areas include the Chips fire in Plumas County, which burned nearly 70,000 acres along the Highway 70 and Feather River corridor. Another is the Ponderosa fire, which burned about 27,000 acres along Battle Creek in Tehama and Shasta counties.
Both regions were the focus of some of the heaviest rainfall in the state on Friday. Stirling City in the Feather River watershed, for example, received 8.36 inches of rain in the 24 hours that ended at 11 a.m. Friday. Clear Creek in Shasta County received 8 inches in the same period.
"We're pulling all nonessential personnel out of those areas that might be at risk from mudslides or debris slides," said Stanton Florea, a Forest Service spokesman.
Jonathan Stock, a research scientist at the U.S. Geological Survey, said landslide risk may also be growing in the San Francisco Bay Area. The agency maintains four monitors there for a project to learn what triggers landslides: two on the San Francisco peninsula, one in Marin County and one near Castro Valley.
Friday's heavy rain nearly saturated the soil at these sites, Stock said, prompting concern that landslides may be imminent. Landslides are more likely when pore space in the soil becomes filled with water. The effect is much like when a sponge can no longer absorb more water and starts dripping, he said.
"Additional heavy rainfalls after that can increase the likelihood of having debris flows happen," said Stock. "We're working with the National Weather Service and we may issue a landslide watch (on Saturday) because we're concerned."
In Sacramento, the downtown area received about 1.7 inches of rain in the 24 hours that ended at 11 a.m. Friday. There were many instances of street flooding and traffic snarls, but no serious problems. In outlying areas, Grass Valley received 4.3 inches of rain in the same period.
The U.S. Bureau of Reclamation late Friday planned to boost water releases into the American River from Folsom and Nimbus dams in response to heavy runoff from the upstream watershed. These releases were expected to raise the river level by 2 feet,submerging many stretches of shoreline.
One of the biggest flood risks is unfolding along the Truckee River. High snow levels in the Sierra Nevada are causing strong runoff into the river, threatening low-lying areas in the town of Truckee and in Reno and Sparks downstream in Nevada.
As of Friday evening, the river was predicted to exceed flood stage in Sparks on Sunday afternoon, possibly inundating portions of Highway 395 and some streets in Reno and Sparks.
The cities of Reno and Sparks, along with Washoe County, declared a state of emergency on Friday to prepare.
Lake Tahoe ski resorts are rejoicing over the storms. Although snow levels were above 7,000 feet and will remain so in the next storm, ski areas at higher elevations got ample snowfall.
"It's been snowing all day, all night," Russ Pecor, spokesman for Heavenly Mountain Resort in South Lake Tahoe, said Friday. "We've got about a foot of new snow in the upper mountain. We could reach 18 inches by the end of the day."
The high winds, though, have shut down many of the resorts for the day, with the closures likely continuing through the weekend.
But Pecor isn't worried. "We'll give up a day or two of skiing to get 12 to 24 to 48 inches of snow," he said.
Peter Avedschmidt, marketing and sales manager for Sugar Bowl Ski Resort, said the wet snow is perfect for building a good base.
"It's heavy and wet snow," he said. "This is amazing snow for this time of year."