Southeast of Geneva and south of Martigny, the Champex-Lac Ski Area has 4 lifts accessing 15km of snowboading pistes with a maximum vertical drop of 700m. Most of the runs are intermediate.
Champex-Lac is part of the Ski St-Bernard ski region, which has six non-interconnected ski areas.
Note: If you plan to head to Champex-Lac for snowboarding by train, here are two great options offered by the Swiss train system SBB. First, there is the discounted Swiss Transfer Ticket which provides a round-trip train ticket from an airport directly to the town near the ski area, plus 50% off any additional train or bus tickets. Second, there is the Snow-N-Rail ticket which provides a round-trip ticket from anywhere in Switzerland combines with a ski lift pass for as long as you need at a total 20% discount (see: http://www.sbb.ch/snownrail ).
Overall, Champex-Lac is the 31st most popular snowboard & freeride destination of all 68 snowboarding resorts in Switzerland.