( CNN ) -- An Illinois woman walked away from a car crash that killed her husband , authorities believe , but they have found no trace of her other than footprints in the snow leading to a road . A search was in its third day Tuesday for Tanya Shannon , 40 , of Ransom , Illinois , according to the LaSalle County , Illinois , Sheriff 's Office . Ground operations began at 9 a.m. with air operations starting at noon , Sheriff Tom Templeton said . `` They 're looking , '' he told CNN sister network HLN . `` They 're expanding their search area just a little . '' Shannon was last seen along with her husband Dale Shannon , 41 , at a Christmas party Saturday night in Streator , about 17 miles west of Ransom , relatives told CNN affiliate WGN and the Chicago Tribune . `` They were dancing together , really cutting up a rug , '' Dale Shannon 's sister Donna Baker , who was at the party , told the Tribune . She said the couple -- married 20 years with four daughters ages 4 to 15 -- left the party arm in arm . Her brother was sober , she told the newspaper , and was driving his wife 's car . About 1:45 a.m. Sunday , a deputy on patrol in a rural area of Brookfield Township found a one-car traffic accident , the sheriff 's office said in a statement . `` The deputy found a male occupant of the vehicle in the driver 's seat deceased , '' the statement said . `` Evidence at the scene indicated that a second person was also in the vehicle at the time of the accident . Further investigation revealed that the second person was possibly the wife of the deceased driver . '' The car slid backwards into a pole , Templeton said , with enough force to break the backs of both the front seats . A relative told the Tribune Dale Shannon 's back was broken . Footprints were reportedly found leading from the car to a nearby road . But there , Tanya Shannon 's trail ends . `` There 's nothing for us to believe there 's any issues other than exactly what happened , a traffic accident that claimed her husband 's life , that she was at least able for a period of time to walk away from and move up to the roadway , '' the sheriff said . `` And once she was on the roadway , that 's where we lost track of her . '' He said he could n't speculate on whether or how badly Tanya Shannon was injured in the crash . `` She was at least able to get up to the road , '' he said . Police have her cell phone , he said . Police have not ruled out the possibility that Tanya Shannon was picked up by someone . But `` if she was able to walk and able to move , how come she has n't contacted any of her family ? '' Templeton told WGN . Tanya Shannon was last seen wearing a red dress -- described by the Tribune as a ball gown -- and a gray fleece hooded jacket , police said . The dress should have made her easy to spot in the rural , snowy landscape . `` We were told from the family she was an extremely loving mother , '' Templeton told the Tribune . For her to just leave with no warning `` would be incredibly out of character , '' Templeton said . `` To be out in the elements as they were that night , dressed only as she was , it 's very doubtful that you can survive terribly long . '' The crash site was remote , Templeton told the newspaper . A nuclear power plant lies to the north , but the area is surrounded by farmland . `` It 's crazy , '' Baker told WGN . `` We 're holding on to every ounce of hope we have , just to hope for ( a ) safe return . ... It 's been like a nightmare you ca n't wake up from . If anybody has anything , seen anything , please , please contact us , because these four girls need something . '' Search and rescue operations have so far involved dogs and aircraft from the Illinois State Police , along with more than 50 searchers , according to WGN and the sheriff 's office . Tanya Shannon is described as being 5 feet 2 inches tall and weighing 125 pounds , with shoulder-length strawberry-blond hair and green eyes , according to the sheriff 's statement . She also wears glasses . It 's very mysterious what might have happened to Tanya , '' Baker told the Tribune . `` We checked the area hospitals and nothing , so we do n't know if someone picked her up and took her somewhere . We just do n't know . '' Templeton said he 's never seen a case like this in his 12 years as sheriff . `` Anything that 's even remotely close has been gone over several times , '' he told the newspaper . Anyone with information regarding Tanya Shannon 's whereabouts is asked to contact the LaSalle County Sheriff 's Office . Ransom is about 70 miles northeast of Peoria , Illinois .
Search for Tanya Shannon stretches into third day . Her husband died in a car crash early Sunday . Footprints thought to be hers were found leading to a road .