Dusty Clark wrote an answer about CamelBak Agent Hydration Pack - 671cu in on April 16, 2014
I'd say it depends on the type of snowboarding you do (as mentioned above, it's definitely not the right pack for backcountry travel) and how often you go. Though it wasn't designed for snowboarding, the reality is plenty of people use their summer packs at the resort - especially if they only go a handful of times a year. The hose is actually insulated, so you'd have a bit of protection on a mildly cold day. (No bite valve cover though, so it won't protect your water from freezing if it drops too low.)
And because this pack was designed for downhill MTB, it has a low profile meant to be chair lift compatible.
So if you only want to bring water and shed layer on a typical resort day, personally I think you'd be happy with it. But if you need anything sport-specific, you should look elsewhere.