Last week the power was out Tuesday 2 pm until Friday 8 pm, 78 hours. I left the lid shut on a 7 cubic foot chest freezer in the garage, where the ambient was in the 70s F most of the time due to the cool weather. When the power came back on, the temperature was about 37 degrees at the top of the freezer. Ice cream in the second layer down had a light bit of crystallization, but no other obvious defects. Other food will be evaluated before being eaten, but it should be safe since it was below or at normal refrigerator temperature, although texture may suffer due to being refrozen.