"CNN meteorologist Gene Norman said," This storm system is always involved in two threats – one for blizzard conditions and another for severe weather. "
Dangerous conditions will wreak havoc for travelers through the rest of this week. Some cities want to get buried under a foot of snow, while others want to get pummeled with a severe storm or flooding.
About 1 million people are blizzard warnings Thursday in parts of Kansas, Nebraska, Minnesota and the Dakota, CNN meteorologist Monica Garrett said.
"Snow with high winds and low visibility is not dangerous at times," Garrett said.
In Nebraska, 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 Dakota, Norman said.
Parts of the Southeast could have been flooded
About 24 million people are under floodlighting through early Saturday, Norman said.
These 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.