Jazz,
I'm in Northeast PA and going to be faced with the same situaation maybe late this season. Liner almost 13 years old and pool over 30. The liner is starting to pull out of the channel and the channel where the bead goes in is falling apart from age. Plastic of some sort. Winters here are harsh too but not quite as bad as yours. Plan is to pull the old liner, inspect the galvanized steel walls and everything else that is exposed. I can peek under the decking and check the steel support members too. If all looks like it will last another 10 years, replace liner. Should be easy. Measurements are already on file, liner was made locally, and the company that did it in 97 is still around. If I decide to replace the liner I'll get some major concrete deck work done too. Otherwise, fill it in.
Al