More than a foot of snow -- 2 feet in some places -- was expected in parts of the Cascades Mountains, the Olympic Mountains in Washington and the Blue Mountains in northwest Oregon by the time the storm moves away, AccuWeather.com reported.
Forecasters said snow drifts could reach 4-6 feet in spots, making travel extremely dangerous.
Snow also was expected in the mountainous areas of California, Idaho and Utah by Monday evening, with higher elevations seeing 6-12 inches of new snowfall.
The Snoqualmie Pass on Interstate 90 in Washington was closed for several hours Sunday because of near-zero visibility blizzard conditions, officials said.
Seattle, Portland, Ore., and Medford, Ore., could see snow turn to rain, with 1-2 inches of rain likely Monday, forecasters said.
In New England, freezing rain in Massachusetts made for treacherous driving conditions, forcing schools to delay their start times Monday, AccuWeather.com said, based on reports from Boston-area media.
Cities from northern New York state to Vermont, New Hampshire and Maine and into Canada could see a mix of snow and ice, Accuweather.com said, predicting 1-3 inches of new snowfall expected in New England.
Rain was expected south of New England into the Mid-Atlantic States.
Colder air behind the storm was expected across the central Appalachians Tuesday.