Help with blown tweeters/power issue

All,

Last night I was happily listening to my new speakers - the largest audio purchase I have or ever will make - when my amplifier’s display  blinked on and off, AirPlay cut in and out, and then wham - the volume jumped up to max with no input from me.  
I immediately shut off the amp, but I fear the damage is done.  The speakers and amp still make sound, but all I hear from the tweeters is a soft, high-pitched hiss. I assume they are blown, and I have no idea what else could be wrong inside the cabinets. 
I have no idea what happened.  My only thought is that the dryer was on nearby and could have caused some sort of voltage spike to the amp.  When I turn on a nearby dehumidifier the lights dim momentarily, which makes me suspicious there is some power issue at play.
I have two questions:

1. What do I need to do to assess the full extent of damage to the speakers?  There are no dealers nearby. 2.  How can I prevent this from happening again?

Thanks for any help.  This has been an awful experience.