Snow is to children as the Bat-Signal is to Batman -- a notice that it's time to get outside and take care of business, be it throwing snowballs (children) or chasing bad guys (Batman). But just as Bruce Wayne wouldn't leave home without putting on the bat suit, children shouldn't leave the house without wearing several layers of clothing. These layers, which are more effective than one big winter coat or snowsuit, should include thermal underwear, wool socks, turtlenecks, sweaters, sweatpants and a water-resistant jacket. And don't forget essential accessories like ski boots, hats, mittens and neck gaiters, which are safer than scarves because they're less likely to get caught on other objects and cause strangulation. When you're dressing a baby or a very small child, a good rule of thumb is to put one more layer on him or her than you would put on yourself [source: Lawrence].
Have the kids come back into the house regularly; it's possible to have so much fun in the snow that you don't notice that hypothermia is setting in (a key sign is shivering). And whether it's snowing or not, make sure your child sports some reflective gear when he or she goes outside. In the winter, it gets darker much earlier than normal, so small objects at play will be harder to spot.