This is an excerpt from Alpine Skiing by Ronald W. Kipp.
Key to Balance: Stance
The motions and movements in skiing are relatively simple. The legs rotate to reorient the skis, they move laterally to create edge, and they flex and extend to decrease or increase pressure on the skis. These three movements are undemanding when taken by themselves. When recombined into the ski turn, however, coordination becomes an issue and balance is upset. Staying in balance is imperative so that these movements can be performed. If we were to peel back one more layer of balance, we would find that stance is the basis of all balance issues. Stance refers to the positions the body strives to maintain while skiing.
What should stance look like? There are numerous ways to describe stance. Many talk of a balanced athletic stance where if you stood on your skis and jumped up and down, you would land in the optimal stance for your body (figure 10.4). This deals with the width of the skis and the amount of flex in the joints. This description is a good start, although it is not enough.
Read more from Alpine Skiing by Ronald Kipp.