If you just want to increase your athletic performance an olympic lifting routine is almost certainly the best option if you are experienced in the gym.
Without prior gym experience, olympic lifting would be very difficult and probably an unrealistic routine.
If thats the case i would reccomend a basic routine like
Low Bar Squats
Plank and Crunches superset
To make it more beneficial to snowboarding, make sure you do squats, leg curls and basically all the exercises other than deadlifts with a slow eccentric phase.