Do not handle dry ice with bare hands. Be sure the room is well ventilated. Ask the dry ice vendor to explain safety precautions. Consider wrapping your freezer in extra blankets. Do not cover air-vent openings because ventilation will be needed when power comes back on.
Blankets are about half as effective as dry ice.
You also can wrap frozen food in thick layers of paper or insulated boxes. Place the parcels in a protected area outside your home if the temperature is in the 30 degree range. Refreezing You can safely refreeze frozen foods that have thawed if they contain ice crystals, are still about refrigeration temperature of 40 degrees Fahrenheit and have not been at refrigeration temperatures more than two days after thawing. Cooked foods that contain sauces, gravies or cooked poultry unless ice crystals are abundant. Melted ice cream.