It really depends on the context. I've never heard of "uwah" (the writer probably made it up; it's not an interjection in English). "Wah" is also not really a word in English, but it's sometimes used in cartoons to indicate some kind of yell. It could indicate surprise, loud crying or screaming, anger, the sound of a crying baby, etc. "Hah" is a laughing sound; "heh" is more like a soft chuckling sound or a very slight laugh. "Uh" is a sound people make when they're thinking about what to say next, or if they aren't sure what they should say, or if they think there is nothing to be said. (For example, if someone asks a question that makes no sense at all, another person might simply respond with "Uh..." to show that the question was nonsense and there is no way to answer.)

Snapped and cracked are both sounds that happen quickly. Yielding can be slow. In addition ‘snapping’ can have the sense of becoming agitated or violent in response to provocation, but it doesn’t have to be used that way. After calmly accepting insults for hours, he snapped and started screaming.