AMNA NAWAZ: Welcome to the "News Hour."

More than half of the nation is bracing for what's expected to be an historic weekend winter storm, one posing dangerous travel conditions, thousands of canceled flights, likely power outages and serious risks of hypothermia.

GEOFF BENNETT: Between now and Monday, the storm will span more than 2,000 miles from Texas to New England, pummeling more than two dozen states along the way with a combination of freezing rain, ice and snow.

Across much of the country, salt trucks are stocking up and snowplows stand at the ready.

Many states are pretreating roads ahead of what's expected to be a massive and menacing winter storm.

At least a dozen states have already declared weather emergencies.

GOV.

KATHY HOCHUL (D-NY): No state will be immune from feeling the effect of Mother Nature's wrath on this weekend.

ZOHRAN MAMDANI (D), Mayor of New York City: What is being predicted right now, whether it's a foot of snow or even a little bit more, would be one of the biggest snowfalls that our city has seen in years.

GEOFF BENNETT: Forming today across the Central Plains, the storm will trudge thousands of miles across the country before arriving in Maine by Sunday.

More than a foot of snow could fall in places in the North.

The south will see freezing rain and sleet.

Almost 180 million Americans are under winter watches and warnings.

JONATHAN PORTER, Chief Meteorologist, AccuWeather: And it will be significant.

GEOFF BENNETT: The chief meteorologist for AccuWeather.

JONATHAN PORTER: There are many communities that are not typically used to dealing with this magnitude of snow and ice that are going to be having to contend with that.

GEOFF BENNETT: Setting the stage, arctic air that is pushing even further south, putting more than 200 million Americans under alerts for extreme cold.

With windchill tonight, it will feel below zero everywhere from the Texas Panhandle to the Midwest and New England.

GOV.

KATHY HOCHUL: You better bundle up.

You will be experiencing minus-40-to-minus-50-degree windchills.

GEOFF BENNETT: Much of the country will stay below freezing well into next week, meaning the snow and ice will not melt.

That could strain electric grids and lead to widespread power outages.

The storm is also expected to paralyze travel.

Nearly 2,000 flights across the country were either delayed or canceled today in advance of the storm.

And officials warned people to avoid driving.

GOV.

ABIGAIL SPANBERGER (D-VA): I am asking all Virginians to stay off the roads as of Saturday night, all day Sunday, through Monday morning.

This will allow not only for the safety and security of our neighbors, but it will allow for faster clearing of roads.

GEOFF BENNETT: Preparing to hunker down, many people have already stocked up on food and supplies, others finding store shelves empty.

JENNIFER GIRARD, Georgia Resident: We may be a little bit early, but we're trying to beat the crowd, yes.

And I used to live in Florida.

And we used to do that all the time for hurricane season.

So it's not so different.

GEOFF BENNETT: Hoping for the best, but preparing for the worst, schools from Chicago to Houston canceled classes today and many school districts across the country are preparing for snow days or remote learning next week.