I'm with you on this. I have a few extra bottles of water left over from the summer in my vehicle right now but they wouldn't do me any good since they are rock solid (I park outside year round).

The only thing I try to do is bring along a water bottle when I'm out & about, but that only provides so much water (less than a litre). I guess a true winter kit really needs a stove or some other method to turn your ice-blocks into something drinkable.