Then put them in a box and leave them alone. Store at least a week's worth of water - 2 quarts to 1 gallon per person per day.
Dry ice is extremely cold and can give a severe burn or damage coolers.
Fill your refrigerator and freezer. Food will stay cold longer when the power goes out and frozen food's as good as a block of ice. Fill extra ice cube trays or plastic jugs and freeze them. Make sure coolers are packed with ice. Please read it.