Why doesn’t an igloo melt from inside? The igloo does melt inside, but not to a great extent. Once the igloo is built, the lady of the house steps in, lights a blubber lamp, turns it up as much as possible and seals the entrance. The snow begins to melt and soaks into the blocks of snow. When the blocks are saturated, the lamp is put out and the door is opened. The frigid outside air rushes in and transforms the fragile snow structure into one of hard, solid ice. Now the igloo can withstand the heat generated by its occupants.