And now for something completely different.
Spin a yoyo around quickly in a near-horizontal loop, horizontal enough that gravity is small compared to the string tension.. The string tension applies the force to accelerate the yoyo in a circle.
Now spin the yoyo in a vertical loop (I think I used to call this trick "around the world"). The yoyo's acceleration is the result of ALL the forces acting on the yoyo, string tension and gravity (forgetting air friction for the moment because it is small). Notice the string pulls harder when the yoyo is at the bottom of it's arc. Gravity and the string tension together make the yoyo go in a circle. The string doesn't have to do as much work (no work done at all due to orthagonal directions) pull as hard at the top of its arc, because gravity is pulling its fair share. The string has to pull doubly hard at the bottom because, now gravity is pulling in the wrong direction to make the yoyo turn.
It's the same with the skier. Your acceleration is the result of all the forces acting on you, gravity and your skis (ok and a bit of air friction, but let's ignore that as it's small at most recreation skiing speeds; once you understand the concept you can add as many forces as you can handle). Your skis have to exert less force on you to get you to go around an arc at the top of your turn, because gravity is doing it's fair share of pulling you into an arc. Your skis have to exert more force at the bottom of the arc because gravity is working against them, trying to pull you out of the arc.
We can flex at the end of the turn (bottom of the arc) and release the pressure, but when we do that our CM comes out of its arc. The more pressure we exert at the top of the turn, and the less pressure we exert at the bottom of the turn, the less we fight gravity, and the faster we reach the chair lift loading area; remember that fact when you want to get in a 2nd "last run".