This would have been kind of humorous if I wasn't in a hurry to deplane. The flight arrived at the gate early and the GA positions the jet bridge for us but then when she shut the motor off it slid away as there was an angled ridge of hard packed snow beneath one of the wheels. She must have tried it 8-10 times over a 10-15 min period. The constant clanging of the bell from the jet bridge was getting rather annoying. Every time she'd have it perfectly positioned, and there it would go rolling away again while we just sat and watched. Finally someone went and got a shovel to clear the area below the bridge.