All sorts of things can be used to anchor a tent down when camping on snow - skis and poles, for instance, do the job well but are not much use if you need to use them during the day but want to leave the tent up. One of us here even used Teva sandals that had inadvertently found their way to base camp!
Top tip! Tough plastic carrier bags make well tried and tested snow anchors - simply fill the bag with snow , attach the guy to the handle, or better still, tie it around the bag, and bury the bag in a hole in the snow. Light, expendable, and very cheap (if not free!).
Photo (taken on an expedition in South America) kindly supplied by John Biggar of Andes Expeditions.