Up to 6 inches of snow is forecast for the high passes under winter weather advisories from the National Weather Service, with snow showers continuing through the evening before tapering off overnight. The advisories cover elevations above 4,500 feet, with the largest totals above 6,000 feet, and Oregon’s rules on chains and traction tires apply on the passes inside them.
Snow Totals For The Cascades
The NWS Portland winter weather advisory splits the range in two. In the North Oregon Cascades and the South Washington Cascades, it runs until 2 a.m. ET Thursday and calls for 1 to 3 inches above 4,500 feet, with 3 to 6 inches above 6,000 feet. Government Camp, Bennett Pass, Timothy Lake, Lost Lake, Larch Mountain, Mount St. Helens and the Indian Heaven Wilderness fall inside it.
Farther south, the Cascades of Marion, Linn and Lane counties are under a shorter advisory that ends at 8 p.m. ET Wednesday. Forecasters expect a trace to 3 inches above 4,500 feet, with the most in the Marion and Linn County Cascades, covering Santiam Pass, Santiam Junction, McKenzie Pass, Willamette Pass, Tombstone Summit, Breitenbush Springs and Waldo Lake. In both zones, Portland warns that roads, and especially bridges and overpasses, will likely become slick and hazardous.
How Oregon Chain Rules Work For Passenger Cars
Oregon posts its requirements on signs at the snow zones, and the wording matters. According to the Oregon Department of Transportation, a “Carry chains or traction tires” sign means the equipment has to be in the vehicle, while “Chains required, traction tires allowed on vehicles under 10,000 GVW” means passenger cars can keep going on traction tires instead of chains, as long as they are not towing. When chains do go on a car or light truck, ODOT requires them on one tire on each side of the primary drive axle…