Revealing mistake: When Daniel is running from Johnny and his gang after the bathroom incident at the dance, there's a lot of fog outside. If you look at one of the trees in the background, you can see that all the fog is being puffed out from behind the tree - obviously a fog machine.
Revealing mistake: When Harkin Banks almost loses control and skis through the lodge, the jump ramp is visible as the woman opens the door. (01:29:45)