It's hard for me to gauge how large those waves are. Without a reference, they don't seem too large. I know they were, but I just don't see it in those pictures.
actually, the waves were not incredibly tall (~30 feet i think)...not much taller than those that regulary hit the shores of beaches around the world. the problem with a tsunami wave is the sheer amount of water behind the breaking front. that 30 foot wall goes far back into the ocean instead of existing just at the breaking point like a normal wave. the tsunami waves were just an overwhelming amount of water that carried an incredible amount of force with it.