A 48-year-old man died in a separate incident near Sedgewickville, Missouri, and a storm-related death has also been reported in South Dakota.
Strong winds, heavy rain and strong thunderstorm are impacting some areas, as well, making travel extremely unsafe through the holiday weekend. The city of Duluth, Minn., issued a no-travel advisory beginning noon Saturday because of a major snowstorm it termed "historic".
Police are also reminding residents not to park on roadways so that crews can plow and keep them clear.
Farther south, precipitation was in the form of rain and thunderstorms.
Another system is forecast to develop in the mid-Atlantic Sunday, moving as a nor'easter into Monday. If this occurs, snowfall amounts could be a few inches higher than predicted, the National Weather Service says.
According to FlightAware, more than 225 US flights had been canceled and more than 2,000 delayed on Saturday alone as of early afternoon.
There were 100 flights canceled Saturday and another 182 delayed at Denver International Airport because of winds.
A record 31.6 million passengers will travel on USA airlines during the Thanksgiving holiday period, according to a forecast by Airlines For America, an American airline trade organization. "Everybody thinks the day before Thanksgiving is the busiest; it is not".
The NWS warned people that roads were snow-covered across the region and most were impassable. The second of the three children turned up later on Saturday. Unsafe conditions will make travel nearly impossible.
Blizzard conditions Saturday are buffeting the High Plains and around Duluth. Wells College is also closed Monday.
Meanwhile, the National Weather Service said the storm was expected to drop 6 to 12 inches (15-30 centimetres) of snow from the northern Plains states into Minnesota, Wisconsin and Upper Michigan.
That was added to 30cm of snow that fell before Thanksgiving. Wind gusts could reach up to 45 miles per hour along the coast, with Cape Ann and outer Cape Cod suffering the worst of the bluster.
All roads in and out of Casper were closed on Saturday morning, including the entire 483km of Interstate 25 in Wyoming. (Cody Bashore/Arizona Daily Sun via AP) PHOTO: This photo provided by Big Bear Mountain Resort shows a fresh snow fall at Big Bear Mountain Resort in Big Bear Lake, Calif., Friday, Nov. 29, 2019.
But then a heavy wall of snow will arrive later in the afternoon and continue through the evening, bringing the heaviest accumulating snow of the storm inland through the evening and overnight into Tuesday morning.