Need help trying to winter a BRS

[Forkliftdriver]

Hello, Today at work I rescued a black rat snake that came off a truck from Georgia. Its very cold here and the snake will surely die if released into the wild here. So I currently have what I believe is a her in a 10 gallon tank with a heat pad no lights unfortunatly. She is 2 and a half feet long. very thin maybe 1/2 inch young im guessing. I dont really like keeping of wild animals but I also didnt want her to die. what temps would I need to maintain to safely put her into hibernation? I know most of you want your snakes to be awake and active but im not a snake person so if it could just sleep like a normal snake would be doing this time of year that would be great.. or if anyone here lives in omaha an would like a free black rat snake that would be acceptable as well