Tom- it's not going to be easy

To get through winter that is.
On the paint with light and fluffy snow, leave about 3/4" of snow on the paint so you don't touch the paint. The remaining snow will likely blow off without any issues to your vehicle or the people behind you. However, when you get into the wet snow and ice, this is where the marring occurs. If you have sheets of ice on your paint, turn the engine and heat on to try and warm it up as much as possible. You don't want the ice to slide on the paint which could happen if you leave it on there and drive. See if you can gently break the ice and pick it up and off of the paint. I would just let the snow blow off and melt in the garage, if it is soft and not ice.
I have heard that salt doesn't cause any issues unless it goes through a cycle of warmth and damp air changes- ie warm garage and hot water. It may be better to let the salt stay on the paint until you have time / weather to clean it off ... not just the paint but underneath as well. As for the DP washes, you shouldn't have too much water on the ground, probably not enough to be conerned about.
Damage is pretty much inevitable in the winter time which sucks. But think of it this way, you'll have plenty of work in the spring

. In the winter I try and not worry about the vehicles all that much. I'll wash them whenever the weather allows but if its going to be below freezing for a few weeks, I'll just hope that my LSP is strong enough to get through the winter

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