After three days of scouring in the frigid cold, investigators have turned up very few clues in their search for the northern Illinois mother of four who has vanished since a weekend car crash that killed her husband.

The only hints of Tanya Shannon since a deputy found the wreck early Sunday have been a set of foot prints in the snow leading away from the site of crash, a slipper and the description of the last thing she was seen wearing: a red dress at a holiday party the couple left after midnight.

"It's just one of those weird situations," said Sergeant Jeff Whalen of the LaSalle County Sheriff's office. "We have no idea what happened."

Dozens of searchers braved frigid temperatures Tuesday to search an area just miles from the couple's home in Ransom. They probed snow banks with poles, operated metal detectors in ditches and even used a helicopter over the flat, snow-covered landscape about 70 miles southwest of Chicago.

Authorities say Shannon, a part-time waitress, may be dead and her body may be buried in the snow, but they also haven't ruled out the possibility that she's still alive.

Family members and friends haven't heard from her since they left the party. On Sunday, a sheriff's deputy found her husband, Dale Shannon, dead behind the wheel of their car near a well-traveled stretch of highway not far from a nuclear power plant. Authorities said it was snowing when the crash happened.

Authorities believe Shannon may have tried going for help. A set of footprints was found in the snow leading away from the car, as well as one of Shannon's slippers _ she had apparently changed out of her heels for the ride home.

"We just want her home," said Shannon's sister Corinne Johnson of Ottawa. "I just want to find her."

Johnson said she last heard from Shannon through a text message around 9:45 p.m. Saturday when Shannon was apparently at the party. It read, "I can text ya 2morrow at dales xmas party all dressed up."

Johnson said she and her sister talked about the condition of the roads before the party, and that Shannon said she wasn't afraid to drive, especially since she had lived in Illinois for twenty years.

At first, Johnson said she thought the disappearance was due to "something silly." But she said she changed her mind as crews searched for a third day Tuesday without finding any clues.

"I wasn't thinking something drastic like this," Johns said. "She just wouldn't walk away from this, this is her life."

More than 35 searchers carefully scanned the area near the crash site. With temperatures hovering around 20 degrees, searchers on foot went out for only an hour at a time, coming back to a command center to warm up and get their blood pressure checked.

"It's just a continuing search; I wish we had more," Whalen said.

The couple's four children _ who range in age from 4 to 15 years old _ are in the care of family.

"The kids are doing as well as expected," Johnson said.

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Information from: WSPL-AM, http://www.am1250wspl.com