Tonight on PBS News Weekend, a powerful winter storm bears down on tens of millions of Americans,

packing a dangerous mix of snow, ice, and heavy rain. Then, four years after the attack on the

U.S. Capitol, we examine the legacy of a day that still divides this country.

And as many as a billion birds die each year in the U.S. from collisions with glass, what one American city is doing to be more feather-friendly.

Folks don't recognize just how serious of a threat this is. Because it's such a

passive threat, this is simply by us existing in the way that we live, having windows. It's a threat

to birds and it's killing birds. Good evening. I'm William Brangham. John Yang is away. A fierce winter storm is barreling across the country, with more than 70 million Americans under winter weather alerts tonight, and four million of those

facing blizzard conditions. At least six governors have declared states of emergencies. Today,

bitter cold winds whipped through the Great Plains and heavy snow-blanketed parts of the northeast.

The massive weather system will reach the mid-Atlantic area later tonight.

In the coming days, it's expected to bring frigid temperatures as far south as Florida.

Matthew Capucci is a senior meteorologist at the MyRadar app.

Matthew, thank you so much for being here.

When you look at what is coming down now and what is forecast to come,

what is it the most concerning to you?

I think for me it's the fact that we're not seeing just snow.

It's the mix, the icy, wintry mix, the freezing rain and the sleet.

It's really complicating things.

You know, when we have freezing rain, it's difficult because that liquid initially washes

all the pre-treatment off the roadways, and so crews can't

really get ahead of the game with situations like this. The other thing, too, is that behind

this system, bitter cold Arctic air is infiltrating the plains, spreading east across the Ohio

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