KANSAS (CNN) -- A massive winter storm spanning 20 states could dump as much as a foot and a half of snow in some places Thursday and bring life to a standstill in parts of the central United States.
About 60 million people -- 20% of the U.S. population -- are under winter weather warnings, watches and advisories in the 750,000 square miles affected.
Dodge City, Kansas, "is in the middle of a bull's eye," said CNN meteorologist Chad Myers. The state should see 16 to 18 inches of snow west of Wichita, with the white stuff continuing up into Nebraska.
Missouri Gov. Jay Nixon declared a state of emergency. Snow, sleet and ice could wreak havoc, and parts of the state could see more than 10 inches of snow.
Kansas City, Missouri, Mayor Sly James also declared a state of emergency. There were 250 snow plows working to clear roads in the city, but residents were urged to limit travel. Kansas City International Airport shut down due to the weather, according to Joe McBride with the city's aviation department.
The city could have its highest daily snowfall since 1912 on Thursday if the prediction of nearly a foot of snow pans out, CNN meteorologist Brandon Miller said.
CNN iReporter Joseph Kopel posted photos of empty shelves in St. Joseph, Missouri, on Wednesday as people stocked up for the blizzard.
Kansas State University canceled Thursday classes, as have dozens of grade schools in the Plains states.
In Wichita, crews have spread salt and sand across roads since Monday. But no matter how much they used, many roads remained slick. Side streets were worse.
Across Kansas, authorities were calling on people to "just stay home," the station reported.
Wichita set a record for daily snowfall Wednesday, with 6.2 inches.
Across the country, numerous flights were canceled or delayed due to weather. St. Louis, Dallas/Fort Worth, Chicago's O'Hare, and Denver had the most cancellations and delays outside of Kansas City, according to FlightStats, which tracks air travel.
United Airlines announced Thursday that certain affected travelers can change their itineraries without paying fees. There is a silver lining for some areas facing the heavy snowfall. "Big chunks of Kansas, Nebraska, Oklahoma and Texas" are facing exceptional drought, HLN meteorologist Bob Van Dillen said.
"You squeeze out the water from the melting snow, and you're talking 1 to 2 inches of water for those dry regions."
On Wednesday, CNN iReporter Doug Simonton in Tulsa, Oklahoma, posted a photo of a car covered in snow and said numerous traffic accidents had been reported around town.
The storm system is huge and carries with it a warmer, wetter Southern component.
It will eventually stretch from the Dakotas to Houston, Myers said. While it will remain snowy in the north, the system will spawn torrential rains and tornadoes along the Gulf Coast and dump freezing rain over Arkansas and Missouri.
"There's going to be a monster ice storm over Springfield and Branson, Missouri. Think of an inch of ice coating everything," Myers said. "Power lines will be coming down. Trees will be coming down."
In St. Louis, freezing rain is predicted to fall on top of a thin layer of snow, which will have "a significant impact on travel," the National Weather Service warned.
North of where the most snow will fall, Chicago could receive as much as 6 inches, CNN's Sarah Dillingham said. The city is running 15 inches below its average snowfall for the season.