A massive winter storm hit the US Rockies and Plains on Friday then punched east, with snow set to assault a 1,800-mile (1,609 km) corridor through the weekend, creating transportation "havoc" in the middle of the country. "St. Louis is seeing its worse snowstorm in five years". "D.C. will end up having at least a day and a half [of snow]. we don't have that many snow events that last that long".
More than 35 million people are under winter storm warnings or advisories across the Ohio River Valley and Mid-Atlantic on Sunday.
The risky weather conditions added to travel misery as the Transportation Security Administration said it would begin closing a handful of security checkpoints at airports around the USA this weekend.
As of early Sunday afternoon, more than 100,000 customers were without power in North Carolina.
Philadelphia is expected to receive a few inches of snow, but areas north of there are expected to be spared, Orrison added.
There is a small chance the southern Appalachians will get enough freezing rain and sleet to turn into an ice event Saturday into Sunday.
More heavy rain also will fall on the already-saturated South. The storm dumped more than 30cm of snow in several parts of Missouri and almost 60cm in one city.
At least five people died in weather-related crashes on roads in Missouri and Kansas, according to the highway patrolmen in both states.
The Missouri State Highway Patrol wrote in a tweet on Saturday that it has responded to 3,918 calls for service, 1,790 stranded motorists, 878 crashes, and 57 injuries.
As the storm heads east, up to 16 inches (41 cm) of snow were likely in western Missouri and St. Louis. Auto accidents resulting from icy, snow-covered roads were already being reported on Saturday evening.
In Kansas City ground crews spent hours clearing snow from Arrowhead Stadium ahead of a playoff between Kansas Chiefs and Indianapolis Colts.
Jefferson City Police Department Sgt. Gary Campbell said between 11 p.m. Friday and around 2 p.m. Saturday, the department responded to 46 accidents. But it cited progress Saturday as crews worked to clear routes and bring "water and food to stranded motorists".
The Missouri Highway Patrol has advised drivers to stay off the roads if possible.
The storm has caused 53 arriving and 39 departing flight cancellations at St. Louis Lambert International Airport with more are expected into Saturday morning, the airport said on its website. The storm is moving east and is expected to persist throughout Sunday, with flight disruptions extending into the work week.