Just got caught in major rain, no power after I turned car off

I'm pretty sure the wiper motor would still have power going to it even though it wasn't turned on. There are several places besides the wiper motor where water can cause a short circuit. Water leaking in the cabin can cause shorts in fuse boxes, dimmer switches, and more.
I can't say the Madelectrical pages are the best way to address the problem. It's certainly not the only way. To bypass that point of failure without finding and correcting the root cause might lead to major heartache later on.
Good luck with it.