Getting over the river and through the woods to whatever house they might be heading to could be more difficult for drivers this weekend as winter storms pound the Sacramento region.

Further ahead, it's going to be a stormy, stormy Christmas.

National Weather Service officials predict a tropical storm will slam Central California on Christmas Eve and into Christmas Day, bringing as much as 15 inches of rain to coastal areas and 4 inches of rain to the Sacramento Valley.

Today, the end of a cold front is moving through the area. The storm sprinkled little rain on Sacramento but is dumping heavy snow in the Sierra Nevada.

Snow elevations are about 2,500 feet and might drop to about 1,500 feet later today, said Eric Kurth, a National Weather Service meteorologist.

The snow had forced the closure of eastbound Interstate 80 at Colfax and westbound at the Nevada state line. Chain controls are in effect on I-80 and Highway 50 near Placerville, Caltrans reports.

A winter storm warning remains in effect until 1 p.m. today, according to the weather service's Web site.

About 3 to 6 inches of snow is expected at Lake Tahoe and near Truckee, with less accumulation on the east shores. Six to 12 inches of snow is expected above 7,000 feet.

Southwest winds between 20 to 35 mph with gusts of up to 60 mph and 120 mph over the ridges are forecast early this afternoon. Heavy winds can create areas of blowing snow and blizzard-like conditions with instant visibility reductions, the weather service states.

The conditions probably will result in dangerous travel and "life-threatening conditions for backcountry activity," the Web site states.

Motorists heading over the Donner Pass and other mountain highways should monitor weather forecasts and prepare for delays.

Travelers heading to Southern California likely will encounter rain as they drive through the Central Valley, as the storm that dampened the Sacramento region is making its way south. Southern California, however, is expected to remain dry today, Kurth said.

Farther north, a winter storm warning will remain in effect until noon today for western Plumas County and into Lassen Volcanic National Park.

Snow has fallen in the mountains of Shasta County and moderate snow and heavy winds are forecast for the Sierra Cascades this morning, the weather service reports on its Web site.

Weather in the Sacramento region is expected to clear Saturday, but another series of back-to-back storms is expected to pummel the region with rain and snow beginning Saturday night and Sunday.

"As a travel day, tomorrow might be a pretty nice day," he said.

The Christmastime storm is the kind the weather service calls an "atmospheric river," because it draws tropical moisture in a jet across the Pacific Ocean that often targets a defined area, directing rainfall like a fire hose.

Often called by the slang term "pineapple express," such storms have been blamed for some of California's worst flooding events.

Because California's reservoirs are largely empty after two years of drought, flooding on major rivers is not expected. But local creek flooding can be expected, said Dave Reynolds, meteorologist in charge at the weather service's San Francisco regional office.

He said Californians planning holiday travels should prepare for the worst and be willing to cancel those yuletide visits if necessary.

"People should start to think. They should really pay close attention to weather reports over the weekend," Reynolds said. "Travel's going to be ugly Christmas Eve and Christmas Day, because it's just going to be raining cats and dogs."

The weather service held a briefing Thursday morning with the state Office of Emergency Services and other key agencies to warn about the approaching storm. These agencies, shorthanded themselves because of the holiday, are making plans to call up vacationing staff members to respond to emergencies if necessary.

"There is a little concern," said Sonny Fong, emergency preparedness and security manager at the state Department of Water Resources. "We're letting key staff know there's a potential, and all three of our incident command teams will be notified and put on alert status."

The storm will be partly triggered by a breakdown in the cold front that has gripped California, Reynolds said. When this happens, it often acts like a funnel that draws warm, wet storms toward California from the tropical Pacific.

In this case, two tropical storm cells are set to be drawn toward the state simultaneously: one north of Hawaii, the other several hundred miles off the coast of Mexico.

Where they converge is still uncertain. Reynolds said predictions show the fire hose hitting south of Santa Cruz. But everyone south of Interstate 80, including Sacramento, should brace for a deluge.

The weather service predicted Thursday the Central Valley could see 4 inches of rain by Christmas Day. Reynolds said the Santa Cruz Mountains and other parts of the Coast Ranges could see as much as 15 inches of rain by Thursday.

Mudslides are a worry in areas burned by recent fires. Heavy snow is also possible on mountain passes.

"It certainly looks threatening, but the details are still to be determined," Reynolds said. "Christmas Day is looking to be the wettest, especially for Central California."

Adding to the concern is the final cold front arriving late Saturday or early Sunday. This may bring a pre-holiday blanket of snow to places like Redding, Auburn and other areas as low as 500 feet. But the next storms, starting Tuesday, will be warmer, adding snowmelt to the flood threat.

"It will be very pretty, but it will also be more dangerous," said Kelly Huston, deputy director of communications at the state Office of Emergency Services. "People just have to be extra careful."

For current traffic speeds, go to www.sacbee.com/traffic. Motorists also may call Caltrans for highway information at (800) 427-7623.

For current weather information, go to www.sacbee.com/weather.

Call The Bee's Matt Weiser, (916) 321-1264.