See more on this story at CNN affiliate WGN.
(CNN) -- The search for an Illinois woman who vanished early Sunday, leaving only tracks in the snow leading to a road after a car crash that killed her husband, has been suspended until weather conditions in the area improve, authorities said Wednesday.
Searchers scoured the rural area Tuesday for any sign of Tanya Shannon, 40, who was from the small town of Ransom.
The search might not resume until the weekend, the LaSalle County, Illinois, Sheriff's Office said. However, the National Weather Service said Wednesday a winter storm may take aim at central and southeast Illinois on Saturday, with the potential of several inches of snow.
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.
Relatives told the media outlets the two had been married 20 years and had four daughters ages 4 to 15. Dale Shannon's sister Donna Baker, who was at the party, told the Tribune "they were dancing together, really cutting up a rug" and 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. A man later identified as Dale Shannon was found dead in the driver's seat.
"Evidence at the scene indicated that a second person was also in the vehicle at the time of the accident," the sheriff's office said in a statement. "Further investigation revealed that the second person was possibly the wife of the deceased driver."
The car slid backward into a pole, Sheriff Tom Templeton said, with enough force to break the backs of both the front seats. A relative told the Tribune that Dale Shannon's back was broken.
Footprints were found in the snow leading from the car to a nearby road. But there, Tanya Shannon's trail ended.
"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 Tuesday. "And once she was on the roadway, that's where we lost track of her."
He said he couldn'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 hasn'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," he 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 can't wake up from. If anybody has anything, seen anything, please, please contact us, because these four girls need something."
Search and rescue operations had 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 5 feet, 2 inches tall and weighs 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 don't know if someone picked her up and took her somewhere. We just don'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.
CNN's Kara Devlin contributed to this report.