Southeast of Zurich and Chur, the Arosa ski area has 70km of pistes served by 13 lifts. In addition, there are about 30km of ungroomed, freeride pistes. New for 2014-2015, there is a new lift linking the snowboarding in Arosa to the Lenzerheide ski area. The Lenzerheide ski area is more easily accessible by train and may make a good base for exploring both ski areas.
Note: If you plan to head to Arosa 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, Arosa is the 52nd most popular snowboard & freeride destination of all 68 snowboarding resorts in Switzerland.