Kansas' governor on Sunday extended a state of emergency declaration to include the new storm.
"This storm has the potential to be more dangerous than last week's storm," Gov. Sam Brownback said. "So, we ask you to stay off the road unless it's absolutely critical. If you have to be out, be prepared with a charged cell phone, an emergency kit with food, water, blankets, flares and a shovel."
The Kansas Department of Transportation reported that many highways in the central part of the state, including Interstate 70, were completely covered by snow and ice on Monday morning.
With two storms dumping massive amounts of snow in quick succession, the weather service warned that structures may not be able to withstand the weight.
Schools closures were also reported from Colorado to Texas, as were the closing of many state and local offices.
All flights in and out of Rick Husband Amarillo International Airport in Texas were canceled until noon on Monday.
"Nothing coming in or out until then at the earliest," airport spokesman Daryl Ware said.
Preston Smith International Airport in Lubbock was also closed, CNN affiliate KCBD reported, and Texas Tech University in Lubbock shut down on Monday because of the storm.
The weather service said visibility was less than one-quarter mile in Amarillo.
And major highways in Texas, including portions of Interstate 40 and U.S. Highways 60, 87 and 187, were closed because of blizzard conditions.
"May see 4-6 foot drifts!" wrote National Weather Service meteorologist Rick Smith on Twitter. "Traveling is beyond discouraged!"
Salt truck drivers were on standby overnight in Oklahoma City.
"Well, we're pretty well prepared right now. We have 28 trucks loaded, plows on," Oklahoma City Emergency Management's Mike Love told CNN affiliate KWTV.
"We run our emergency snow route. We'll run that until it's free and clear. And if this stuff comes in like they're saying tomorrow, with these high winds, look forward to some drifting."
In Norman, Oklahoma, the University of Oklahoma closed Monday.
In Wichita, Pajor said the city used half of its road-clearing salt and sand in last week's storm.
To the east, Kansas City is expecting 9 to 15 inches of snow Monday night into Tuesday, according to the National Weather Service, and officials are telling residents to stay off the roads.
To the west, more than 9 inches of snow was reported in some areas of Denver by early Monday. Airlines in the Colorado capital were working to return to normal operations a day after more than 200 of 1,500 flights had been canceled and hundreds more flights were delayed because of the weather, according to the Federal Aviation Administration.
Up to 19 inches of snow was reported in Jefferson, about 70 miles southwest of Denver.
Forecasts of similar conditions raised alarms throughout the Plains, leading to crowded stores as residents prepared.
Amanda Roberts, an entrepreneur and blogger in Warrensburg, Missouri, where snow is expected to begin Monday night, went to the stores ahead of the storm.
"The snow has everyone stocking up on groceries," she said in a Twitter post. "Fresh produce is basically gone, but I got the last gallon of chocolate milk. I call it a win."
Rain, flooding the issue in Southeast
While millions will see snow -- including Chicago, where 3 to 5 inches of snow and sleet are expected Tuesday -- rain may rule for the next few days in parts of the Southeast.
In Mobile, Alabama, on the Gulf Coast, residents prepared for the possibility of heavy rain and wind gusts as strong as 30 mph by Monday night.