UPDATE: here is a youtube video someone captured of the actual transformer explosion at the power plant. you can see the youtube video doesn’t really correspond w/the video capture from twitter below. the twitter video shows the flashing glow up in the sky – nothing at ground level. a friend of mine saw this and passed it along too: (substations do emit a continuous hum but what is described below seems to be felt and heard in a broader sense. i have asked where she lives in relation to the substation and will post if i hear anything.)

SOURCED FROM HERE.