Honestly I am not a great snow boarder by any means lol. I've only messed around on tiny boxes/rails and tiny little jumps, more like G-outs than jumps. I would say if you know how to fall, a helmet/spine guard and butt pants should cover you pretty well. Wrist guards would be the only other thing I could think of getting if you have a tendency to land on them.
The only reason I say spine guard is a must/definitely recommended is because I pinched nerves in my back in October last year, than again in January on that rail, than twice this summer on my bike the few times I didn't wear armor. It felt like broken ribs, and it's not fun. I'm planning on wearing my camelbak snow boarding this year for back protection, that thing has saved my back when I went over the bars countless times. I know it sounds dumb, but I swear it has, and I don't have to shove bottles into every pocket in my jacket and pants.
If you just know your limits, and when you can push them, you'll be fine.