Kelly Starrett is the man! 5-15 minutes of mobility work each day can be beneficial. I feel that mobility work is "better" than yoga to gain mobility and increase your resistance to injury. Yoga is great for some things, but a yoga clas isn't going to target hip mobility, knee tracking and ankle flexion. Tree, warrior, cobra, chavasana, cat, cow, down-dog poses do nothing for me as a snowboarder. Using a lacrosse ball on my calves, rolling out on a foam roller and doing hip and ankle opening drills before and after a hard day of carving works wonders.
I also want to say that I love my yoga, the right class and instructor can be pretty intense. Inverted holds and balances, back bends, and partner work is really fun and feels great. I still do mobility work as it's far more beneficial for the functional aspect. Yoga is more feel good spiritual.