I probably get around the same amount of snow up here in NH, and we use a lot of salt too. What I do is after a major storm or a major application of salt (you will know, your car turns white) is go to a brushless car wash and buy the cheapest option (spray, wash, rinse). You should probably wait for a day that is above freezing. This will get the majority of the salt off. If I really want to be thorough, I do a manual spray and also get the underbody as well (including wheel wells).