An igloo (Inuit language: iglu, Inuktitut syllabics: ᐃᒡᓗ, "house", plural: iglooit or igluit) or snowhouse is a type of shelter built out of snow, originally built by the Inuit. Iglu is the Inuit word for a house or home built out of any material, and is not restricted exclusively to snowhouses, but includes traditional tents, sod houses, homes constructed of driftwood and modern buildings. Outside of Inuit society, however, "igloo" refers exclusively to shelters constructed out of blocks of compacted snow, generally in the form of a dome.
Although igloos are usually associated with all Inuit, they were predominantly constructed by people of Canada's Central Arctic and Greenland's Thule area. Other Inuit people tended to use snow to insulate their houses, which were constructed from whalebone and hides. Snow is used because the air pockets trapped in it make it an insulator. On the outside, temperatures may be as low as −45 °C (−49.0 °F), but on the inside the temperature may range from −7 °C (19 °F) to 16 °C (61 °F) when warmed by body heat alone.
There are three traditional types of igloos, all of different sizes and all used for different purposes.
The snow used to build an igloo must have sufficient structural strength to be cut and stacked in the appropriate manner. The best snow to use for this purpose is snow which has been blown by wind, which can serve to compact and interlock the ice crystals. The hole left in the snow where the blocks are cut from is usually used as the lower half of the shelter. Sometimes, a short tunnel is constructed at the entrance to reduce wind and heat loss when the door is opened. Due to snow's excellent insulating properties, inhabited igloos are surprisingly comfortable and warm inside. In some cases a single block of ice is inserted to allow light into the igloo.
Architecturally, the igloo is unique in that it is a dome that can be raised out of independent blocks leaning on each other and polished to fit without an additional supporting structure during construction. The igloo, if correctly built, will support the weight of a person standing on the roof. Also, in the traditional Inuit igloo the heat from the kudlik (qulliq) (stone lamp) causes the interior to melt slightly. This melting and refreezing builds up an ice sheet and contributes to the strength of the igloo.
The sleeping platform is a raised area. Because warmer air rises and cooler air settles, the entrance area acts as a cold trap whereas the sleeping area will hold whatever heat is generated by a stove, lamp or body heat.
The Central Inuit, especially those around the Davis Strait, lined the living area with skin, which could increase the temperature within from around 2 °C (36 °F) to 10–20 °C (50–68 °F).
The 1922 documentary Nanook of the North contains the oldest surviving movie footage of an Inuit constructing an igloo. In the film, Nanook, whose real name was Allakariallak, builds a large family igloo as well as a smaller igloo for sled pups. Nanook demonstrates the use of an ivory knife to cut and trim snow block, as well as the use of clear ice for a window. His igloo was built in about one hour, and was large enough for five people. The igloo was cross-sectioned for filmmaking, so interior shots could be made.
An igloo (or iglu) is a shelter (a place for people to stay warm and dry) made from blocks of snow placed on top of each other, often in the shape of a dome (like half of a hollow ball). They were used in winter as temporary shelters by hunters when they were away from their regular homes.
They were most often built in places where a lot of snow covers the land for weeks or months at a time, such as the far north of Canada and Greenland. Most igloos are built by native Inuit people (sometimes called Eskimoes). As they learned to build them better, sometimes people would build larger igloos that would last longer and hold more people, even for dancing.