Boots are good, another thing that you can look into if you're interested is a paw wax like Mushers Secret which creates a barrier between the paw and the snow and ice.
Mushers Secret-all season paw protection for your dog
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 5 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010