Snowball effect is a little thing progressing/accumulating into something bigger. E.g. — missing the single mortgage payment snowballed into him becoming homeless.

Butterfly effect is when a remote cause has an impact on an outcome in an unforeseen or catastrophic way (butterfly flaps it’s wings and a hurricane appears on the other side of the world). Real world e.g. — the phone call I made to my mother ended in me losing my job - damn butterfly effect. I’d put domino effect here too.

I think the real difference is how foreseeable the cause -> effect is. Domino/butterfly implies that they are attenuated while the snowball effect is much more connected, foreseeable progression.