The Minneapolis area is expected to get four to six inches of snow from daytime through the end of the game, according to Accuweather.com. All that precipitation on an artificial surface could lead to severe footing problems, which is one reason the Bears moved Saturday's practice to Northwestern University, so they could become better acclimated to playing outside on turf.
The game-time temperature is expected to be 19 degrees with a wind chill of minus-1. Snow began falling at approximately 10 a.m. CT and continued into late afternoon.
An examination of the turf by ESPNChicago.com revealed that the surface was indeed hard as well. FieldTurf typically feels soft and spongy, but the surface in the end zone didn't give at all while being pushed and stomped on.
All NFL fields have heating coils underneath to combat icy conditions, but because snow tore a hole in the Metrodome roof, the game was moved to TCF Bank Stadium on the campus of the University of Minnesota. The school's field does not have heating coils beneath it.
So precipitation falling during the day combined with freezing temperatures could make for dangerous conditions.
A green tarp covered the playing surface at the stadium most of the day, and workers labored to remove snow accumulating on the tarp. The tarp was partially removed at about 4 p.m. CT and was completely removed by 6 p.m. CT. Snow would obviously cover the playing surface quickly.
As snow continued to fall, workers attempted to keep the field relatively warm by using four heaters to blow hot air on the turf from underneath the tarp. All four heaters were located along the home sideline, so the hot air was reaching only one half of the field at that time.
The stands were mostly clear of snow, with the exception of the fresh batch. Snow accumulation was starting to become a problem outside the stadium, but plows were being used to try to clear paths for foot traffic.
Despite the frosty conditions, fans started to line up outside the stadium to try to capitalize on the first-come, first-serve seating policy.
Vikings banners were visible at the top of the stadium, the only real reminder that an NFL game is set to be played here later in the evening.
Many NFL players on the Bears and Vikings have questioned why a league game would take place at the stadium.
Vikings punter Chris Kluwe was the latest player to question the playing surface on Sunday.
"The field is as hard as concrete an hour and a half after they took the tarp off, and anyone that hits their head is getting a concussion," he tweeted. "I find it interesting that the NFL can claim an emphasis on player safety, and then tell us the field is fine. It's beyond hypocritical. ... I can only hope, however unlikely, that no one gets catastrophically injured at the trainwreck that's about to take place tomorrow night."
The Bears played the Baltimore Ravens last season in a cold-weather game on artificial turf and were blown out 31-7.
Jeff Dickerson covers the Bears for ESPNChicago.com and ESPN 1000. ESPNChicago.com's Michael Wright and ESPN.com's Kevin Seifert contributed to this report.