Are you just supposed to leave the salt on the bottom of your car until it warms up?

Hi. Long time driver, first time northerner. I've never lived somewhere where the roads get salted like they do here. Kind of worried about my frame rusting, do people usually wait until the weather warms up in a few months to wash it off or is there a touch-free car wash that operates during the winter? Please teach me the traditions of your noble and storied culture. Thank you.