PORTLAND, Ore. – Scattered snow is adding a new wrinkle to the Northwest's deep freeze.
A Winter Storm Warning is in effect for the Portland area until one o'clock Tuesday afternoon, and the extremely cold weather is producing snow showers in and around the Portland area.
There is also a slim chance of potentially dangerous freezing drizzle, but KATU Meteorologist Dave Salesky says most locations will only see snow, but areas north of Portland could see more ice.
Snow flurries began falling in some areas Monday afternoon, including Hillsboro, McMinnville and Southeast and Northeast Portland. None of it was sticking, however.
Salesky says there is a possibility that by Tuesday morning, about a half-inch of snow could be on the valley floor, including in downtown Portland.
More alarming, however, is the chance of freezing drizzle.
"It only takes less than .10 inches to create a sheet and get cars slipping around," KATU Meteorologist Rhonda Shelby said.
Shelby said she expects the ice to be patchy in Portland, but to be worse from Vancouver to Olympia. She said the snow is likely to be more of a distraction than a danger.
"When it starts coming down pretty hard, people start freaking out and get distracted (on the roads)," she said. "I don't think the system is big enough to hit anybody really badly."
Watch the forecast:
Salesky says Thursday could be the worst day of the week. A warm, wet system will be approaching the coast, but the cold air will still be in place, making more snow and freezing rain likely, especially east of Interstate 205 in Troutdale and the Columbia River Gorge.
By Friday, Salesky says the cold should over and the normal Oregon rain will return.
During wintry weather, TriMet says riders should be prepared for delays.
This year the agency says it now has more than 200 buses with drop-down chains that drivers can use by pushing a button.
TriMet says it has also installed more "ice caps" for the MAX's overhead wires to help keep ice from building up on them.
Stay informed about TriMet service during the cold and snow by going to its website: http://www.trimet.org/alerts/
Portland's Bureau of Transporation warned drivers Monday night to be ready to delay their commute if streets and roads are too icy.
"If there is a mess," said PBOT's Dianne Dulken," then the best, safest trip is the trip not taken. So stay home if you can for an hour or two - whatever it takes - and/or take TriMet."
Road crews spent Monday night applying de-icer to streets and roads across the Portland/Vancouver area. They'll switch to sanding if the conditions deteriorate.