How long does a freezer keep food safe without power?
A full freezer holds a safe temperature for about 48 hours if the door stays closed. A half-full freezer holds for about 24 hours with the door closed. The 72-Hour Power Outage Plan quotes FoodSafety.gov: food may be refrozen if it still has ice crystals or is at 40°F or below.
Read The 72-Hour Power Outage Plan