Give the camera/lens plenty of time to acclimatise to the temperature and avoid condensation. Put in a plastic bag before you move from one temperature zone to another, suck out as much air as possible, leave for at least an hour in the 'new' zone before using. If you do get condensation, put the camera and lens in a dry plastic bag with dry rice; the rice will absorb the moisture and is easier to get hold of than silica gel.
Keep batteries in your pocket when outside for as long as possible before use; performance drops with temperature.
Use a polariser for those deep blue skys.
Remember your camera will try to average exposure = grey snow, so dial in some '+' exposure compensation. I'd start around +1.5.
Is there that much difference between the two lenses to warrant taking both?
Have fun!!