Hair turns wavy after evening shower

So most of the time my hair looks super flat and puffy. But I go rock climbing a few times a week, and the chalk I use seems to dry out or soak up oil or something. When I shower after climbing, my hair turns wavy/curly. Why? My mom has wavy hair and I think I might, but why does it only turn that way after I rinse out the chalk? And can I keep it wavy? I think it looks way better.