How do you explain this?

Situation: a storm has taken out the electricity supply. Wake up in the middle of the night to a high pitch tone similar to an alarm or siren. Go down stairs and find the main room glowing from the ajar door. Reach in and turn off the light switch..... this is impulse but there is no electric supply because the upstairs lights have all been left on. When the switch is turned off the noise stops. Enter the room the TV is glowing and fading. Weird. Explanations welcome