Yes, KeithT, the "+1 and 2/3rds stops" is for those bright sunny days that are really dazzling - sunglasses weather. In the UK, if there's snow around it's usually accompanied by dark grey clouds! But even there are exceptions.
All you need is the ability to use your camera on the dreaded M (don't be afraid). Shooting in snow is a great way of teaching yourself how to take a photo rather than always allowing your camera to get it wrong for you.