The interior of an igloo is a dome-shaped space with ice and snow-packed walls. While the size of an igloo can vary considerably from a small hunting or fishing shelter to a larger gathering place, the interior walls are always designed in a spiraling pattern to provide support and strength for the ice structure. An igloo can be very simple or more detailed to form complete living quarters during winter months.
Upgraded igloos often include amenities like a stove for cooking, extra head space for standing and a sleeping platform for a better night's rest. Because the snow and ice continuously melt and refreeze due to body temperature inside the igloo, the ice of the igloo becomes increasingly frozen and solid within a couple days of building, creating an airtight structure. Several air holes in the walls of an igloo prevent suffocation, especially when cooking inside.
Extra head space is added to the interior of an igloo by digging out the floor once the igloo is complete. A platform for sleeping in an igloo consists of a series of ice blocks that raise the bed off the floor and allow for a warmer night's sleep. An entrance is created to the igloo by digging a hole beneath its wall and covering the entrance with ice blocks to prevent wind from blowing into the igloo.