Last Updated Feb 7, 2014 3:24 PM EST
PORTLAND, Ore. -- A second winter storm in two days is bearing down on Oregon and southwestern Washington, this one topped with ice that could make highways more treacherous in some areas and knock out electricity.
Snowfall starting late in the morning Friday will be widespread, dropping a foot or more in mountainous parts of southern Oregon and 2 to 8 inches in western Oregon valleys that got slammed Thursday, the National Weather Service said.
Many school districts in the region canceled classes for a second day Friday. Portland International Airport reported nine flights canceled but said most flights were expected to continue.
The snow was expected to turn to freezing rain Friday night and Saturday in many areas, especially the southern and central Willamette Valley and the Pacific coast. That will turn roadways icy and increase the possibility of power lines drooping and falling, resulting in outages, forecasters warned.
The first storm dropped more than a foot of snow on parts of the Pacific Northwest and left one person dead in a massive Interstate 5 pileup in southwest Washington. It also closed schools and offices.
The snowstorm caused a string of car crashes on I-5 near Albany, Ore., essentially closing the highway there for five hours, the Oregon Transportation Department said.
The department advised residents to avoid driving unless absolutely necessary and to use public transit whenever possible.
"We are not expecting to see road conditions improve today; in fact we can expect them to get worse, especially with the next band of snow that's going to hit us," spokeswoman Kimberly Dinwiddie told CBS Portland affiliate KOIN-TV. "So we're still encouraging people to not drive unless they absolutely have to."
The last back-to-back snow event like this in the region hit in December 2008, said Colby Neuman, a National Weather Service meteorologist in Portland.
The big I-5 pileup that killed one person and injured others occurred across the Columbia River in Washington state's Clark County.
At least half a dozen tractor-trailers were involved in the collision on the snow-covered freeway, The Columbian reported.
Washington State Patrol Trooper Steve Schatzel said several people were trapped in the wreckage. One suffered injuries described as critical and two others suffered serious injuries.
Oregon State Police Lt. Steve Mitchell described a 25-vehicle pileup on I-5 near Albany as "pure chaos."
Traffic backed up for miles. Only minor injuries were reported.
Oregon's largest city, Portland, recorded 3 1/2 inches of snow by Thursday evening. Cars slipped and slid as commuters left work early. Some good-hearted residents helped push vehicles that got stuck.
A school bus slid on ice and collided with a car Thursday afternoon in Aloha, west of Portland. Firefighters said one of the children on the bus was taken to a hospital with knee pain.
Snowfall totals as of Thursday night included 13 inches in the small town of Vernonia, Ore., northwest of Portland, and 10 inches in St. Helens, north of Portland along the Columbia River. Snow also fell along the Oregon coast; the community of Wheeler got 9 inches.
In the Willamette Valley south of Portland, Corvallis got 9.3 inches and Albany reported 7 1/2 inches.
In the Columbia River Gorge that divides Oregon from Washington, snow was accented by 30-40 mph winds that gusted to 60 mph, Neuman said.
In southwest Washington, Ridgefield got 9 inches of snow, Woodland got 7 and Longview got 5.The storm struck quickly Thursday morning, dumping snow on the Albany region and then spreading north.