The first component is best seen from a third person pespective. Watching a skier notice the tip and tail of the ski always follow the incidental slope angle. This means the direction we face has a lot to do with the elevation of the tip and tail relative to the feet. Traverse and the ski is mostly level, straightline and the tip is lower than the feet and the tail is higher. Foot to foot elevation (vertical seperation) works the same way, where the dowhill foot is always lower than the uphill one.
The second component is most easily understood when we shift to the accelerated perspective of the skier. Pressing down on the tips drops them below the feet until they encounter enough support from the snow. It is this reaction force that pushes back enough to make the tip bend and move back upward towards the knee. Many talk about experiencing this in deep powder more than on groomers but it occurs in every turn we do. Moguls are another especially good example of this. Cresting a mogul we drop the tips into the trough and the tips are again below the feet and the tail are above the feet. But if we drive the tips down with tongue pressure we will be levered too far forward as the skis run into the top of the next bump where the tips will rise as they slide up onto and across that mogul face. It makes more sense to dorsiflex the feet to keep the tips in contact with the snow. Which is a move borrowed from reaching slalom turns BTW. But that is a topic worthy of it's own thread, so I will not hijack this thread to explore that idea further.
Many have already described the difference between steering and braquage. Tip pressure increases as we steer the ski through the turn and this again causes the forebody of the ski to bend and "rise". In braquage the edge angles are so low that the tips rising and falling occurs more as a function of the incidental slope angle and the direction the skis are facing on that slope.
Edited by justanotherskipro - 4/13/15 at 6:23am