In skiing and action sports, balance is not a static notion, as it would be balancing on top of a ball, but a very much dynamic notion. In fact, we maintain balance through athletic movement.
Dynamic balance includes anticipating the movements required in the near future and possibly compensating ahead of time. Using the momentum and inertia of different parts of the body to leverage against etc
We work on developing dynamic balance not just to prepare for the beginning of the season, but throughout the season as well:
Here's an example of lane changes: