I have got to ask, are you living in an older home, now that you've moved in the last year? Could it have been because of old faulty wiring?
Also want to mention that we have whole house fire alarms installed last year and one of the tips they told us was ... do not leave a space between the plug and the outlet (you know how sometimes the plug just doesn't want to push all the way easily?) push it all the way nice and snug ... dust can build up on the plug points and a fire can start from there.
so happy that you were able to unplug fast and safely, and that your quilt was safe!