The hard snow walls of an igloo are good insulators that keep in body heat and also the heat generated by oil lamps, these are known as qulliq. This is why traditional igloos are commonly made out of snow rather than ice and this is because solid ice does not retain heat as well as blocks of compressed snow. In addition, the walls block the wind, which is often so bitter that it can make freezing temperatures feel many degrees colder. Also, insulation capabilities actually increase a few days after construction. Body heat and sun exposure cause the inside of the igloo to melt ever so slightly. When the igloo is unoccupied during hunting expeditions, the melted snow freezes over, turning into ice. Gradual thawing and refreezing turns the entire structure to solid ice, making it not only superstrong, but warmer than ever.
