While the term 'gnar' may get used a lot by freeskiiers, it isn't a term exclusive to skiing.
Urban Dictionary gives it two meanings:
1. A shortened version of the word gnarly, meaning high on the scale of dangerousness and coolness. Often used among the skateboard crowd
"That switch heelflip was gnar"
2. Snow.The white stuff. You like it.
"Lets shread the gnar"
These are both very applicable to skiing, but it's a term also used in other 'extreme' sports.
gnar is anything and everything
I don't know the slang term for a guitar but the slang term for playing the guitar is "shredding the gnar" so I'd imagine that the slang term is gnar.
Gnar stands for Gonkey's Numerical assessment of Rad. Invented by Shane McConkey, this is like a game that is played on ski slopes. The term Gnar is used by skaters, skiers, and surfers, or any sport in which something might be radical. For more info on the original watch "The Game of G.N.A.R." at unofficialnetworks.com or read the rules in the book Squallywood.
It can also be called Nordic Skiing...
Traversing means skiing back and forth across the fall line
Slalom is the name given to water skiing with one ski.
This term refers to the sport of skiing.
Workaholics - 2011 The Future Is Gnar 3-20 is rated/received certificates of: Netherlands:12
gnar wall-e
It means a sunny blue sky day with fresh powder snow... perfect skiing conditions.
Crosscountry skiing, otherwise called Nordic skiing or XC skiing, is a colder time of year sport that includes skiing across significant distances over fluctuated landscape. Nordic skiing is the name given to it because it was first practiced in Scandinavia and other Nordic countries during the winter as a means of transportation. Crosscountry skiing varies from downhill skiing in that it includes skiing on compliment territory, and the skis are longer and more slender, permitting the skier to skim over the snow as opposed to cut turns. It is a popular winter exercise and endurance sport that is enjoyed by both recreational and competitive skiers.
'Skiing' is a term used to describe the sexual position where a boy (or a girl) gets between two guys, while facing in the same direction, and jerks them both off, thus imitating cross-country skiing.