Wow.
Aliens?
Perhaps.
You might try looking for a dismembered cow in that forest behind your house. It is a known fact that some of the smaller craft use a grid leak bias device that radiates a powerful signal in the 120KHz region, easily picked up by your homes wiring when the craft is overhead. It is actually this energy that raises the hair on the back of your neck.
OK back to reality. Do you use AHP, or are you one of the Homeseer users? My Homeseer has on rare occasions suddenly went nuts and locks up for a couple of minutes.
Did you see anything in the activity monitor?