It's a simple staircase, yet Disney elected not to leave well enough alone. They added theming here that doesn't really serve any functional purpose (and in fact takes up valuable space) - but that's all the more reason to love it.
When you get right down to it, the entire mountain is unnecessary theming. 99% of water parks around the world just build plain-jane staircases and then unthemed slides and tubes. Disney conceals everything in the effort to transport you somewhere else--the mountain is a vital part of that. Little flourishes like this themed avalanche area wouldn't even have been necessary... but they are great, and they do add to the experience, don't they?
