The only advantage that most drivers will ever have with a manual transmission on ice and snow is while stopping. The manual trans. will disengage power when the clutch is depressed. The automatic will continue to push you forward unless you shift it into neutral. Starting up from a stop most drivers will find the automatic easier as it is less apt to break traction due to the internal drag of the fluid drive abosrbing some of the torque being applied by the engine. A manual transmission will break traction more easily due to the juggling act that the driver must perform with the clutch and accelerator pedals. Personally I prefer a manual transmission but that is for reasons other than winter traction.

Mark
Alaskan driver since 1978