system
Given the following post, respond as if you're commenting on Reddit:
human
My PhD advisor is leaving before I start my program. Advice?

I was recently accepted into a PhD program in counseling psychology. I chose the program because of a particular professor whose (somewhat niche) research interests aligned with my own. He subsequently chose me to join his lab. Unfortunately, I just found out that he will be leaving the university before I even begin the program this fall. He is also moving out of academia, so I can't follow him, and there aren't any other faculty members in the program with research interests similar to my own (based on their bios, at least). Any advice?
gpt
Yeah - this is not great. 

Contact the Dept head for sure and see what they recommend.

If the department is somewhat functional, one of the professors will step up and take responsibility for you. Keep in mind your research direction is not set and you should be open to new ideas as well as the reality of the situation.

If the department isn't functional, you will likely fall through the cracks. 

Good luck.