Salt to prevent ice question

Ok it's a stupid question, but I was wondering how I need to go about this. It snowed in my area all night. It is 37 degrees today and the snow is already very slowly turning to water. However, tonight will get down to 7 degrees and tomorrow's high is only going to be 20. Should I salt tonight before it goes down to 7 degrees so that i can ensure it won't turn to ice tonight/tomorrow? Or do i wait until morning to salt, even if ice has formed? I have little kids and I just don't want them to slip and get hurt.