Chris Pietsch / The Register-Guard via AP

Del Queener of Puyallup, Wash., puts chains on his semitruck trailer tires as he prepares to drive over Oregon's Willamette Pass during a snow storm Monday.

The strongest Northwest storm of the season dumped more snow in the mountains and even some lower elevations after earlier firing gusts up to 80 mph along the coast and knocking out power to thousands in the Seattle and Portland areas.

With 3 feet of snow already delivered by Tuesday morning, the Cascades in Washington were expected to get another 6 inches by Tuesday night and then 8-16 inches on Wednesday.

The storm is headed east along the U.S.-Canada border, said meteorologist Danny Mercer.

"It doesn't look like a big snow or wind producer for the rest of the U.S. It looks like the biggest impact was here," he said.

But another storm is splitting off from that — "part of the same trough" — and heading south. It's likely to bring snow along the Rockies, include the Boulder-Denver area, late Tuesday into Wednesday, Mercer said.

Wet snow pellets that looked like hail hit an area of south Everett during the Monday evening commute, depositing ice along Interstate 5. That snarled commuter traffic in both directions. 

The highest winds hit Sunday evening with an 84 mph gust recorded at the mouth of the Columbia River and an 81 mph gust on the central Oregon coast, said meteorologist Scott Weishaar in Portland.

Winds early Monday hit 60 mph on the Washington coast and 55 mph in the south Puget Sound area, said meteorologist Ted Buehner in Seattle.

Winds brought tree limbs down on power lines. Seattle City Light had 11,000 customers out of service at one time. Puget Sound Energy had 17,000 outages, mostly in the south King County area, southeast of Seattle.

Portland General Electric responded to dozens of power outages in the metro area. Pacific Power had about 10,000 outages throughout western Oregon.

Winds knocked a tree onto a home in Lakewood, Wash., near where a 2-year-old was sleeping, but it missed the baby's crib. Winds also were blamed for sinking two boats on Lake Washington at Kirkland, Wash., and the fire department helped two people who were sleeping on one of the boats, KOMO Radio reported.

Snow was also on the ground in parts of eastern Washington, including Spokane, but downtown streets were clear by Monday afternoon. 

"A wide variety of winter weather is clearly affecting the entire state," Buehner said. "It's the strongest storm of the year, so far."

Wind speeds of more than 60 mph were reported in eastern Washington at Pullman on Monday morning, and power company Avista reported thousands of customers without power in its large service area. Winds of more than 50 mph were reported in Spokane, and a tree fell on two homes. No injuries were reported.

Winds delayed work on the Hanford nuclear reservation in southeast Washington. A large accumulation of tumbleweeds blocked some roadways, the Tri-City Herald reported. Washington Closure Hanford canceled outdoor environmental cleanup work because of the winds.

Snow accumulations in the Oregon Cascades will total 1 to 2 feet, Weishaar said.

Four construction workers at a cellphone tower project on Steens Mountain in southeast Oregon were stranded when their snow cat became stuck in a drift Saturday. They waded through waist-deep snow to reach a heated shelter with electricity.

Harney County rescuers were turned back both Sunday and Monday by white-out conditions. The weather was expected to improve Tuesday, said Matt Fine, Harney County search and rescue coordinator. 

The Associated Press contributed to this report.

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This traffic camera image shows crews responding to an overturned car on State Route 599 north of Seattle, Wash., on Thursday.

SEATTLE -- A day after a major Pacific storm covered Washington state in snow, the Seattle area on Thursday dealt with a new menace: an ice storm that shut down the airport and toppled trees -- cutting power to some 200,000 homes and businesses, cutting off roads and taking the life of a man on his ATV.

Some commuters gingerly tried to make it to work as a freezing rain iced over roads, but others stayed home.

Several major roads were cut off by fallen trees weighed down by ice and snow. Near Issaquah, a suburb east of Seattle, a man on his ATV was killed by a falling tree, NBC affiliate KING5.com reported.

Gov. Christine Gregoire declared a state of emergency by late morning, a move that would allow her to deploy National Guard troops if needed.

The National Weather Service used the Emergency Alert System to break into Thursday morning broadcasts with an ice storm warning until noon for the Seattle area and southwest Washington. That was later extended to 2 p.m.

A mix of snow and ice was expected Thursday afternoon and overnight before warmer temperatures bring rain and the possibility of flooding.

Downed trees also led to the outages, and many customers might not see power back for days.

"We think it will be 3 to 4 days … maybe longer," Puget Sound Energy said on its Facebook page, adding that it was dealing with 500 outage locations.

Sea-Tac Airport closed early Thursday so that its three runways could be de-iced. Two runways had reopened by midday, but many airlines reported flight cancellations.

Lines hundreds of people long snaked around nearly every ticket counter, with many passengers on their cell phones as they tried furiously to rebook their flights. Reader-boards showed the vast majority of flights canceled or delayed.

At Snoqualmie Pass just east of Seattle, Interstate 90 closed Thursday morning for avalanche control.

Freezing rain and ice pellets caused numerous accidents in the Seattle area, where drivers are mostly inexperienced with driving in snow or ice. The last widespread freezing rain in Seattle was in December 1996, said meteorologist Jeff Michalski at the Weather Service office in Seattle.

On Wednesday, downtown Seattle saw two inches of snow but Olympia, the state capital, got 11 inches and other areas were also in double digits.

The Washington State Patrol said it responded to more than 700 accidents on Wednesday.

Thursday's forecast was for a mix of snow and rain, and the Weather Service warned that urban and small stream flooding was possible Friday, when another, albeit milder, storm was expected to hit the state. Rain and temperatures in the 40s would start melting snow on the ground.

STORY: Child drowns, mom presumed dead in storm

The National Weather Service also issued flood warnings for several Oregon rivers and several roads were closed because of flooding in Salem and nearby Turner and Scio.

Authorities called for voluntary evacuations of the town of Mapleton, Ore., which has about 1,000 residents, and some nearby areas because roads are expected to flood.

Don Ryan / AP

Downtown business are protected from flood waters with sandbags in Scio, Ore., on Thursday.

Residents of 22 homes were urged to evacuate near tiny Lewisburg, Ore., about 80 miles south of Portland, due to unstable land and a landslide.

The Associated Press and Reuters contributed to this report.

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SEATTLE -- A Pacific storm blanketed downtown Seattle in a few inches of snow but smothered other parts, especially south of the city and in the mountains, where several feet of new snow fell.

For Seattle, the storm proved less extreme than originally forecast, with the National Weather Service lowering its outlook for possible snow accumulations from up to 10 inches to around 6 inches, meteorologist Dustin Guy said.

But Olympia, the state capital, saw 10 inches by late Wednesday morning.

By midday Wednesday, 20 inches of snow already had fallen on the rural town of Rochester, just south of Olympia, said Rob Harper, a spokesman for the state Emergency Operations Center.

There were 95 accidents in an eight-hour period in Pierce and Thurston counties, which include Tacoma and Olympia, State Trooper Guy Gill said Wednesday morning. Most were spinouts.

"You need to pick a rut and stay in it. If you get off the beaten path, you're in deep trouble," Gill said. "I saw a guy in my rear mirror — I saw headlights and tail lights and headlights and tail lights again as he spun around off the road."

John Brecher / msnbc.com

Composite views of downtown Seattle as seen from the Jose Rizal Bridge on Tuesday, top, and Wednesday morning, bottom. Click the images to see a slideshow of other before and after pictures.

"For the first time in my career I had to put chains on," Gill said. "You stay in the path laid down on the freeway. You get off that, you are in trouble."

Most schools in the Seattle area were closed on Wednesday due to the storm, said Lesley Rogers, a spokeswoman for the Seattle Public Schools district.

Children took advantage of the rare snow day to sled down hilly streets, especially the city's tallest incline, Queen Anne Hill, which towers 450 feet above nearby Elliott Bay.

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Four inches of snow was measured at the city's Sea-Tac Airport by mid-morning, and the Seattle suburb of Bothell was blanketed with nearly 7 inches of snow, the Weather Service reported.

John Brecher / msnbc.com

This street in Seattle's Beacon Hill neighborhood is seen Wednesday morning, bottom, and a day earlier.

Alaska Airlines canceled over 40 flights departing from or arriving in Seattle as a result of the storm, the company said. Southwest Airlines cancelled six flights into Seattle early in the day but resumed all flights by mid-morning, said company spokeswoman Ashley Dillon.

The snowstorm also slowed traffic on city streets and freeways.

"There's been tons of collisions, it's been really slick out there," said Julie Startup, a spokeswoman for the Washington State Patrol.

The State Patrol responded to reports of 75 collisions and spin-outs in King County alone, which includes Seattle, between 5 a.m. and 10 a.m., Startup said.

Normally temperate Seattle is more accustomed to steady rain than snow in winter, averaging just 6 to 7 inches of snow each year, said National Weather Service meteorologist Brad Colman.

The storm also was blamed for "scattered" power outages, mostly in southwestern Washington state, Harper said.

Some 30,000 homes and buildings were without power in Portland, Ore., on Wednesday morning as trees made heavy by ice downed power lines.

Gusts up to 110 mph were reported along the Oregon coast.

The Cascade Mountains could see 1 to 3 feet of new snow through late Wednesday, and officials warned of high avalanche danger there. Some computer models showed the Cascades potentially receiving up to 4 feet of snow, reported KING5.com on Wednesday morning.

PHOTOBLOG: Before/After photos of the Seattle snow

The snow was expected to taper off on Wednesday night, giving way to a mixture of rain and snow more typical for the region, Weather Service meteorologist Johnny Burg said.

But Harper said freezing rain could bring about additional problems in parts of Washington state.

"Freezing rain increases the chances that power lines will come down," he said.

He added the governor could later declare a state of emergency if conditions worsen.

Reuters and The Associated Press contributed to this report.