have heard a great deal about using a Polarizing Filter to decrease the glare of Ice and Snow while deepening the blue of the sky and myself personally I prefer and recommend a Neutral Density Filter. True that a polarizer will decrease the glare but you run the risk of increasing the blue cast of light on the snow. A graduated Neutral Density filter which transitions, either abruptly or gradually, into the other half which is clear. It is used to bring an overly-bright part of a scene into the dynamic range of film or sensor which would decrease the brightness of  snow and sky. Wear layers, review the forecast, minimize the use of your tripod, don't open the legs to their full capacity. The snow and ice could damage them. When you get back to your vehicle keep your camera cold and enjoy your hot chocolate when you get home!