I drive a 2001 Pontiac Grand AM (4 cylinder engine). It's extremely cold here. Yesterday the high was just 10 degrees and it's currently only 15 degrees. Yesterday when I was arriving home for lunch, I hit a small pile of extremely hard snow with my front passenger tire. My car made a small popping sound, but I assumed it was the snow breaking up. When I was returning to work, I noticed my car was creaking towards the front passenger tire. At that time (it was about 7 degrees), it creaked almost constantly. Going home, the creaking was about the same. When I parked at home, it creaked when I turned my wheel left and right. Going to work this morning, it creaked some, but mostly when I went over any kind of bump in the road. I also noticed that my driver's side front tire was creaking too. When I parked at work and turned my wheel left and right there was no creaking. When I went to lunch today the creaking had seemed to subside (it was about 13 degrees then). However, when I came back it was still creaking when I hit any kind of bump. Any ideas what the problem may be?