A skin track is the single-file trail kicked into the snow by the lead skier on a ski-touring climb. The lead skier sets the angle, switches direction at the kick turns, and breaks trail through unconsolidated snow; the rest of the group follows in the same line, which is faster, less tiring and substantially safer than each skier breaking their own trail. The Norwegian word is sporsetting - track-setting - and the lead skier is the sporsetter.
On a guided topptur in the Lyngen Alps or the Sunnmøre peaks, the guide sets the skin track and the clients follow at a steady spacing of three to five meters. The angle of the track is the most-discussed technical decision: too shallow and the climb takes all day, too steep and the clients's skins slip on the kick stride. The standard target is around 12 to 15 degrees of climbing angle, with kick turns wherever the terrain forces a change of direction.
A well-set skin track is a small piece of mountain craft. Norwegian guides talk about it the way English fishing guides talk about reading a river. For the visitor, walking up a properly-set skin track on a clear morning in late April, the snow holding firm in the shadow and softening to corn in the sun, is one of the small defining experiences of the sport.