A strong snowstorm that began in the Northwest on Sunday will gain more steam early this week.
A potent cold front will move across the region through Tuesday, producing heavy snow, powerful winds and periods of whiteout conditions.
By the time the storm fades, many high elevations of the Washington and Oregon Cascades will be slammed with more 24 to 48 inches of snow and wind gusts exceeding 50 mph. Similar winds will hit parts of the northern Rockies in Idaho, Montana and Wyoming, with 12 to 24 inches of snow.
Snoqualmie and Lookout passes along Interstate 90, as well as Stevens Pass on U.S. Highway 2 and Willamette Pass on Oregon state Route 58 will be trouble spots for truckers.
Truckers will have to slow down and likely chain up. Typically, roadside messages will be posted when chain controls are in effect in certain areas. Knowing the chain laws in the impacted states can mean the difference between delivering loads safely and potentially damaging freight and equipment, as well as shelling out hefty fines.
Thunderstorms and heavy rain will drench lower elevations and coastal areas at times. Localized flash flooding is possible in areas mainly along and west of Interstate 5 and along U.S. Highway 101. These areas will also experience damaging winds that may blow down trees and power lines.
The National Weather Service has issued winter storm warnings, winter weather advisories, high wind warnings and high wind watches across almost the entire Northwest. Driving will be touch and go, whether in wet or snowy conditions, with possible road closures.
Related: Chaining up: 4 pro tips for truckers
Major lanes of concern
- Interstate 5 from the Washington-Canada border to Mount Shasta, California.
- Interstate 84 from Portland, Oregon, to Echo, Utah.
- Interstate 90 from Seattle to Rapid City, South Dakota.
- U.S. Highway 2 from Everett, Washington, to Glasgow, Montana.
- U.S. Highway 101 from Olympia, Washington, to the Oregon-California border.
Other notable weather this week
Look for more rounds of severe storms and potential tornadoes from the Plains to the South during the first half of the week. The best chances Monday are from Texas and southern Oklahoma to the lower Mississippi Valley. Tuesday, the risk will be from the Deep South to the Southeast Coast, then stretching from the Deep South to the Tennessee Valley on Thursday.