Oops, Sorry, I guess I should have been more verbose
in my statement... (
I agree with all you say above RicB. In my short statement I wasn't referring to lateral linear momentum
but rather the sideways rotational momentum
created about an axis through the CM by initial counter-steering. For a skier to initiate a reorientation from one side to the other it takes a bit of force (torque) to make that rotation happen. That's what I was referring to.
Once started, it takes a counter-torque to eliminate continued sideways rotation (because of the now-existing angular momentum). This matters because once the skier initiates lateral rotation from one side to the other... how do they stop it? What stops the skier from just planting the new inside-ear into the snow?
My answer is increased centripetal force from the engaging skis. And not just increased, but increased just beyond
the point the skier would be back in normal lateral balance. This occurs for a brief moment, then the skier settles into a more refined state of lateral balance. This is true for ILE and OLR also.
In the video (at 2:36) you can see this multi-move rebalancing act with the bicycle and again with the motorcycle a moment later. That little extra 'wobble' after the initial move is not a mistake, it's a brief, necessary over-steer to stop the over-rotation laterally that would otherwise occur.
If you've ever gone over a sharp drop off just after turn initiation (at speed) you may have found yourself toppling sideways while in the air. Once the skis leave the surface they can't stop our lateral rotation (angular momentum) and we end up with a hip check on our new inside-hip.