In deep snow (10-15cms) I had to disable traction control to get up a 0.5km fairly steep hill. I was the second car up. Otherwise with TC on, if you got stuck, it would not rev as TC stopped both driving wheels spinning - which was teh only way to get up. (Hump back bridge plus sharp corner ay bottom of hill meant gaining any speed before teh climb was impossible.
Took me three attempts to work out how to do it..