A woman stands in high snow in Tieton Dam, Wash. on Saturday, Dec. 24, 2016.
© @ciaraschultz / instagramA woman stands in high snow in Tieton Dam, Wash. on Saturday, Dec. 24, 2016.
A major holiday winter storm packing heavy snow and the threat of blizzard conditions is bearing down on the northern-tier states from the Rockies to the upper Midwest and is likely to shut down major highways in parts of the northern Plains as it rolls eastward Christmas Day and Monday.

The stretch of northern states can expect blowing snow and drifts from strong winds, possibly in excess of 60 mph, making travel hazardous, the National Weather Service warns.

In addition, snow and a wintry mix is possible from the Great Lakes to the Northeast, with rain and a few thunderstorms likely from the lower/mid-Mississippi Valley to the Mid-Atlantic on Saturday, the weather service says.

map storm

In the West and mountain states, over a foot of snow is expected in the Sierra, Cascades and parts of Utah and southern Colorado, while at least six inches is likely in the northern Rockies, and high elevations of Arizona and southern California, The Weather Channel reports.

Several inches of snow, possibly heavy at times, is also forecast for low-elevation cities such as Boise, Salt Lake City and Flagstaff, according to The Weather Channel.

Over a foot of snow is possible in parts of North Dakota, northern and western South Dakota and even as far as northwest Minnesota, with at least 6 inches of snow in the High Plains of Montana and northern Wyoming.

Forecasters warn many roads, including major interstates, will likely be shut down Christmas Day and into Monday in the northern Plains and High Plains, as high winds kick up blizzard conditions in the area.

The Weather Channel also warns of the danger of tree damage and power outages from the high winds and heavy snow.