I have a real close up on a wave crashing on a short I'm working on. I'm trying to make as precise as possible but I'm not satisfied yet.
I have good real big wave sounds as source that I tried to pitch down and mix with things like cannon roars... but it's hard to make something really powerfull and convincing at the same time. The fall is not so hard to make as the sound of the wave rising, I guess (the cannon roar has worked reasonably for the first). It's a mad man's job trying to "shape" water, really.