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Kitsap Sun, Larry Steagall, Associated Press
In this photo taken Sunday, Jan. 15, 2012, Maliah Bowden, 13, tries to catch a snow flake in her mouth, in Manette, Wash.

SEATTLE — Seattle, a city more accustomed to rain than snow, prepared Tuesday for a potentially major snowstorm to hit as the city's mayor urged residents to stay off roads.

Many school districts in the western part of the state, including Seattle, canceled classes for Wednesday, when the area was expected to get several more inches of snow.

Snow has been falling steadily in parts of western Washington and Oregon since the weekend, but National Weather Service meteorologists said the biggest amounts could come on Wednesday. The new round of snow was expected to start falling just before the morning rush hour in the Seattle area, meteorologist Doug McDonnal said.

"Wednesday is going to be a good day to stay at home," said Brad Colman, another Weather Service meteorologist in Seattle. "The road is going to be treacherous."

The Seattle metropolitan area could get 3 to 5 inches of snow, with 3 to 6 inches in the Olympia area and 1 to 2 inches north of Seattle. The Cascade Mountains could see 1 to 3 feet of new snow through late Wednesday.

If the past is any hint, even several inches of snow has the potential to paralyze the city of Seattle. The city owns relatively few snowplows, and Seattle drivers are mostly inexperienced with driving in snow or ice.

Crews were salting and sanding streets, some local agencies prepared to open emergency shelters and commuters made plans to stay at home. Officials warned of high avalanche danger in the Cascades.

Bec Thomas, who lives Camano Island north of Seattle, was hunkering down. She stocked up on bottled water and food. While her children built snowmen, made snow angels and sledded in nearly a foot of fresh snow, she made food that could be reheated on her woodstove.

The last snowstorm knocked out her power for a week.

"We take it very seriously," said Thomas, a fine arts photographer. "We'll probably be snowed in until Thursday."

John Lee, a graphic designer who lives in Mill Creek north of Seattle, decided to work from home Tuesday when he looked out his window and saw several inches of snow on the ground and more falling.

"Snow is beautiful to look at but it's kind of a hindrance for us to work and commute," said Lee, 23, who works in Seattle. "This is the first snow we've seen all season, so it's a bit exciting in that way. I hope it doesn't escalate to something bigger."

The weather service issued a winter storm warning from Tuesday night to Wednesday night for much of Western Washington. A storm warning was also issued for much of eastern Washington from early Wednesday to Thursday night.

Snow from the new storm was expected to start falling first on the Washington coast, where conditions will also be windy.

Forecasters predicted that about 6 inches of snow could fall on Spokane by Wednesday with several more inches falling Thursday. The Pullman area could see as much as 12 inches of new snow by Wednesday night.

Washington state troopers advised motorists to plan ahead and be prepared.

"The No. 1 thing is to drive for the road conditions," Trooper Keith Leary said. "People need to slow down, take their time. If they're not prepared, don't get out on the roadways."

In Oregon, log trucks spun out on ice, school districts closed bus routes and colleges cancelled early classes. The amount of actual snowfall varied across the state, but traffic accidents and clogged roadways were the norm across a northern strip of the state that extended from the coast to the Cascades and included the northern lowlands in the Willamette Valley.

Snow has steadily been falling in Olympia since Sunday, and large snowflakes continued to fall Tuesday with several inches on the ground at the Capitol.

In Portland, the city was still stinging from the fallout of a 2008 winter snowstorm that caused major traffic backups and public transportation delays.

This year, the city's Bureau of Transportation spread a de-icing solution over major roadways. The solution, calcium magnesium acetate, is considered less toxic and non-corrosive.

Portland does not use rock salt to prevent ice.

"We're not expecting huge accumulations of snow," said Bureau of Transportation spokeswoman Cheryl Kuck. "But we're ready for anything."

Snow on Tuesday canceled or delayed classes in many school districts in the region. Seattle Public Schools, the state's largest school district, closed schools two hours early on Tuesday.

AP Writer Rachel La Corte in Olympia and Donna Blankinship in Seattle contributed to this report.