( CNN ) -- A massive winter storm spanning 20 states dumped more than a foot of snow in some places Thursday and brought life to a standstill in parts of the central United States . About 60 million people -- 20 % of the U.S. population -- were under winter weather warnings , watches and advisories in the 750,000 square miles affected . Statewide emergency declared . 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 , and residents were urged to limit travel . Kansas City International Airport shut down because of the weather , according to Joe McBride with the city 's aviation department . The city picked up 7.6 inches of snow , a record daily snowfall , the National Weather Service said . CNN iReporter Joseph Kopel posted photos of empty shelves in St. Joseph , Missouri , on Wednesday as people stocked up for the blizzard . Authorities in Kansas had closed a 240-mile stretch of Interstate 70 west of Salina earlier in the day . Two dozen soldiers from the Kansas National Guard later searched the interstate and U.S . Highways 54 and 400 farther south for any stranded travelers . In Wichita , despite crews spreading salt and sand across roads for days , many roads remained slick . Side streets were worse , CNN affiliate KSN reported . Gov . Sam Brownback called for people to stay home . `` If you do n't have to travel , do n't do it , '' the governor said . The storm started to wind down Thursday night in Wichita after leaving 14.2 inches of snow over two days -- the second highest storm total in the city 's history , according to the National Weather Service . Topeka received 9.2 inches of snow . The University of Kansas closed two of its campuses -- in Lawrence and Overland Park , both near Kansas City -- through Friday because of the weather . Across the country , flights were canceled or delayed because of weather . St. Louis , Dallas/Fort Worth , Chicago 's O'Hare , and Denver had the most cancellations and delays after Kansas City , according to FlightStats , which tracks air travel . United Airlines announced Thursday that certain affected travelers can change their itineraries without paying fees . Track winter weather across the U.S . Some drought relief expected . There is a silver lining for some areas facing the heavy snowfall . `` Big chunks of Nebraska , Kansas , 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 . '' 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 . A large system . 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 was forecast to spawn torrential rains and tornadoes along the Gulf Coast and dump freezing rain over Arkansas and Missouri . Arizona golf tournament suspended because of snow . `` 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 . Southern downpours . Severe thunderstorms moving in from the Gulf of Mexico are expected to bring 2 to 6 inches of rain to New Orleans and Montgomery , Alabama , according to CNN 's weather center , before rolling up toward Atlanta . The torrential rains could lead to significant river flooding , as flood watches are still in effect from last week 's heavy rains . Heavy winds , hail and tornadoes are possible , the National Weather Service said . Downpours are expected to continue into Friday . Desert dwellers stunned . On Wednesday , the winter storm system left a rare thin layer of snow across the deserts of Arizona , New Mexico and southern California as far south as the border with Mexico . `` I 've been here for over 10 years and I 've never seen it snow like this , '' Kayla Avery of Tucson , Arizona , said in a CNN iReport , which came with a video of the snowfall . `` There is more snow on the ground in Tucson today than I have seen in over 30 years living here , '' Carrie Tucker said in another iReport . Mona Jensen of Dolan Springs , Arizona , posted photos of her 8-acre property blanketed by snow . Katie June in Yucca Valley , California , shared a shot of a snow-covered cactus . `` Some of the larger ones are having a hard time , '' she wrote . `` But they all enjoy the drink ! '' Joan Dedmon in Tuscon , Arizona , also found snow on cacti and shared a picture of a snow-covered birdfeeder . She said it confused the hummingbirds who were trying to get a meal before dark . CNN 's Steve Almasy , Mike Pearson and Pedram Javaheri contributed to this report .
NEW : Wichita receives 14.2 inches of snow over two days . The storm dumped more than a foot on the city, and caused flooding in some areas. Kansas crews search I-70 after shutting down a 240-mile stretch . NEW : Snow even reaches southern California and the Arizona desert .