One hundred million Americans are waking up Thursday to snow, ice, and freezing rain. This latest round of winter weather has claimed the lives of at least a dozen people across the South.
It's also been crippling travel and has left almost half a million homes without power.
The day began with more than 4,000 flights cancelled, leaving about 5 million passengers stranded nationwide.
"I was anticipating going home Thursday, had plans for Friday, but that's now going to be cancelled," stranded traveler Tisha Mason said.
The powerful system could dump more than a foot of snow on Boston, Philadelphia, and Washington, D.C. It's already shut down the federal government Thursday and closed schools up and down the East Coast.
"I'm played out with the snow. It's making my job twice as hard," postal worker Harold Grimminger said.
Three people were killed when an ambulance crashed on an icy road in west Texas and caught fire.
A Dallas firefighter was also killed after being knocked from an interstate ramp and falling 50 feet.
In Raleigh, N.C., people abandoned their cars on frozen roads, and many ran for cover after one trapped car caught fire.
"Don't put your stupid hat on at this point in time," North Carolina Gov. Pat McCrory admonished. "Protect your family. Protect your neighbors. Let's protect each other."
Meanwhile, hundreds of thousands of homes and businesses have lost power in the Carolinas and Georgia, where ice and wind gusts snapped power lines and tree limbs.
The roof of one North Carolina church collapsed. And one Georgia woman's daughter was nearly crushed when a pine tree fell on her home.
"Hearing the tree crack and watching it fall from my window and landing on my daughter's room was very traumatic," Georgia mom Kenya Parker said.
This harsh winter has already depleted salt supplies in cities in the mid-Atlantic and Northeast. It's also caused school systems to run out of snow days.