A brutal winter storm packing wind gusts of up to 80 mph was marching toward the nation's interior Monday,

Threatening to pound a swath of the nation with snow measured in feet.

Almost 15 million people in more than a dozen states faced foul weather warnings or watches Monday.

Blizzard or winter storm warnings were in effect for parts of Oregon, Nevada, Idaho, North Dakota, South Dakota, Wyoming, Colorado, and Nebraska.

"This system will then stall across the central Plains into Thursday, producing several days of heavy snow

And blowing snow, including blizzard conditions, and freezing rain extending into the Upper Midwest," the National Weather Service Storm Prediction Center said in its advisory.

"Severe thunderstorms, tornadoes, and flooding will be possible in the South."

Pockets of those states could see 2 feet of snow, the center said.

The weather service in Colorado said the storm would arrive late Monday

last through Tuesday, likely bringing "whiteout conditions" and road closures.