I think you need to ask yourself several questions:
How good am I at snowboarding?
What are the conditions I will be boarding in?
What is the difficulty of the runs or parks I will be in?
As a snowboarder myself, I know that I would trust myself with delicate equipment on some runs and others I would not. Furthermore, there are some conditions in which I would never take anything delicate. If you plan on boarding in anything icy or packed granular, even the most experienced riders will catch a lip.
Really the question you have to ask yourself is "How often do I plan on landing on my back?"
Good luck finding a bag. As for myself, I wouldn't trust myself with a dslr and lenses because of all of the unforeseen circumstances.