I never understood why people buy milk before a storm. Unless you have a baby a perishable refrigerated item is probably a bad idea when the power might go it.
I can see my hubby do this. He drinks about half gallon a day or more if he doesn't have stuff outside to do. Him and my sons were always big milk drinkers and I used to go through 2 gal a day. It is funny though and perhaps they want it for cooking. Biscuits, gravy, cornbread and the like..... Pudding.
