Spline Split Science episode #11. We demonstrate 2 different turns you can do on a switchback. A tank turn and a kickturn. Ideally you make your skin track to avoid rapid changes in direction such as a switchback but in steeper terrain it's unavoidable.
Spline Split Science #12 tackles a few tricks to dealing with icy skin tracks. Might feel awkward but standing tall and putting your weight on your heels is the way to gain more grip on your skins.