Need Help and Insight

I have a client where ranking has fallen for no obvious reason. They were holding at position 3-4 on page one for awhile under "Anchorage Web Design". Out of nowhere a company that was ranking towards the bottom shot past them.
The company i work with is biancafrankdesign.com
and the comany that went past is https://alaskawebstudio.com

I just don't see any obvious reasons why this would've happened. Any insight or help would be appreciated.

Maybe they just built their site decently(the company that shot past them) or did something very blackhat.