US: Adverse winter weather forecast over northwestern regions through at least Jan. 10 /update 1

Adverse winter weather is forecast across parts of the northwestern US through at least Jan. 10. Another winter storm system is forecast to cross the Pacific Northwest late Jan. 8-9 with several feet of heavy snow and strong winds across the Cascades. Blizzard conditions are likely. More than 30 cm (12 inches) of snow is likely in the higher elevations of the Northern Rockies Jan. 9-10. Heavy snowfall will likely combine with blustery winds to cause low visibility and hazardous driving conditions across the affected area.

As of late Jan. 7, the National Weather Service (NWS) has issued winter storm warnings across parts of far northern California, northern and central Idaho, far northwestern Montana, southwestern and western Oregon, and far northeastern Washington. Blizzard warnings are in place across the Blue, Cascades, and Olympic mountains. Winter weather advisories, winter storm watches, and high wind warnings are in place across much of the rest of the affected area. Officials could update and extend the coverage of weather alerts over the coming days.

Snow accumulations are likely across the affected area, especially at higher elevations. Lesser accumulations are possible where sleet and freezing rain mix with the snow, and precipitation is less intense. In addition to the heavy snow, strong wind gusts will likely lead to periods of blowing and drifting snow in some areas. Blizzard conditions are possible. Sporadic power outages could occur throughout the affected area.

The winter weather will likely cause ground and air transport disruptions over the coming days. Traffic and commercial trucking delays are probable along regional highways. Dangerous and challenging driving conditions are likely on secondary and rural roads in the affected states as maintenance crews prioritize clearing major routes. Authorities will probably close stretches of highways if driving conditions become too hazardous. Flight delays and cancellations are likely due to ground stops and deicing operations at regional airports.