While parts of the Midwest are blinded by whiteout conditions, the Southeast is bracing for torrential rain and flooding.
All this spells more nightmares for holiday travelers heading into New Year's weekend.
"This storm system was always comprised of two threats -- one for blizzard conditions and another for severe weather," CNN meteorologist Gene Norman said.
Here's what's happening in different parts of the country:
'Our town has come to a complete standstill' in the Midwest
About 1 million people are under blizzard warnings Thursday in parts of Kansas, Nebraska, Minnesota and the Dakotas, CNN meteorologist Monica Garrett said.
"Snow with high winds and low visibility will make travel in this area dangerous if not impossible at times," Garrett said.
In Nebraska, whiteout conditions and crashes forced the closure of Interstate 80 between Lexington and North Platte
"Travel in the area is not advised," Nebraska State Patrol said on Twitter.
The storm system is expected to dump 6 to 12 inches of snow in Colorado, Kansas, Nebraska, Minnesota and the Dakotas, Norman said.
Sharon Kay Oelkers captured video of snow blinding her town of Elwood, Nebraska, on Thursday morning.
"Our town has come to a complete standstill," Oelkers told CNN. "I work at the local grocery store and even we are closed and we never close."
Parts of the Southeast could get flooded
About 24 million people are under flood watches or flash flood watches through early Saturday, Norman said.
Those watches cover parts of Louisiana, Mississippi, Alabama, Georgia, Tennessee, Kentucky, Virginia, West Virginia and the Carolinas.
Atlanta, home of the world's busiest airport, could get up to 6 inches of rain by the end of this weekend -- potentially snarling holiday travel.
Fierce storms hit Gulf Coast states
Coastal parts of Texas are getting walloped Thursday after severe weather caused in-flight injuries and spiked a football game a day earlier in the Dallas area.
"Severe storms including damaging winds and an isolated tornado are possible along the Gulf Coast from Louisiana to Alabama today," Garrett said Thursday.
"Winds will also be strong from the Gulf Coast northward to the Ohio Valley, with winds gusting up to 45 mph throughout the day today."
