(CNN)-- Another Pacific storm is expected to pound the West Coast this weekend and could unleash flash flooding, mudslides and debris flows, just a week after similar rains left widespread devastation.
Flood watches and winter weather advisories now exist throughout Oregon and Washington state, and a coastal flood advisory will continue through Monday for the San Francisco Bay Shoreline, the National Weather Service said Saturday.
In all, a moisture plume from the China Sea across the Pacific could drop between 4 and 6 inches of rain on the coast and as much as 8 inches in Oregon. The Cascades could receive 6 to 10 inches of new snow, and northern California could experience 3 inches of rain
"These disturbances, along with their surface cold fronts, are forecast to bring heavy rain for the coastal areas of the Pacific Northwest, with some amounts in excess of 4 inches possible by Sunday morning," the National Weather Service said. "Very heavy snow in the higher mountain ranges could reach 1 to 3 feet with copious moisture being forced up the topography."
As the West Coast front energizes climates across the country, rain and cold could create delays in holiday travel from Tuesday through Wednesday in the Southeast, the Ohio Valley and the Eastern Seaboard's Interstate 95 corridor, CNN forecasters said.
A Christmas Eve storm could strike the Great Lakes basin from Minneapolis to Chicago to Detroit, delivering snow showers and freezing temperatures. The storm would taper off by Christmas Day, said CNN meteorologist Karen Maginnis.
More than a week ago, storms pummeled the Pacific Coast, killing two people in Oregon when trees fell, knocking homes into the sea in Washington state, burying houses in a California rockslide and even spawning a rare tornado in Los Angeles. Power outages struck hundreds of thousands of customers.
The weekend warnings of debris flows conjure up a tragedy in March, when a landslide killed more than 40 people in Oso, Washington, about 60 miles northeast of Seattle.
Oregon geologists also expressed concern, especially in areas hit earlier by this year's wildfires.
"Landslides will be a reality in future major flood events," Bill Burns, engineering geologist with the Oregon Department of Geology and Mineral Industries, told CNN affiliate KATU. "And because Oregon's population is growing, more people, places and property may be at risk."
The forecast promised a rocky start to next week's Christmas holiday and was immediately posing problems for early holiday travel.
"There's such a headwind that I'm getting terrible gas mileage today," Elaine Howard told CNN affiliate KCRA. She drove from Redding, California, on Friday to visit her son in Herald.
One upside for travel, though, has been low gasoline prices. The national average on Saturday was $2.43 a gallon, the lowest level in five years and 70 cents lower than last year, AAA said. That price could fall as low as $2.25 by New Year's Day, AAA said.
At those prices, AAA is projecting 98.6 million Americans will travel 50 miles or more from home during the year-end holidays, an increase of 4% over last year.
"Lower gas prices are filling stockings with a little more cash to spend on travel this year as travelers are expected to pay the lowest prices since 2009," said Marshall L. Doney, AAA president and chief operating officer.
Luis Gonzalez told KCRA that such prices were one reason he chose to drive rather than fly his family from Portland, Oregon, to Orange County, California.
"I found the tickets. But it was like $1,500 for four people. So I said, 'Eh, I can go back and forth with the gas in my car,'" Gonzalez said.
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