If I am going to be away from my cabin for a couple of weeks, or more
I have a water bottle thats half full of water with a drop of food color that
was frozen upside down.<the food color lets you see the water level> when frozen solid turn it upright,then if the water has melted back down into the bottom, you know the power has been out a day or more and it may not be safe to eat anything from the frig.

CARVER