Igloo Structure Directions

Approximately a foot of snow must be on the ground for construction to work. Begin by flattening out a circular area, using your feet a pair of skis or snowshoes. The circle's diameter should measure as long as the tallest person.

With the igloo's location picked out, and the snow stamped flat, blocks of snow will make up the igloo's walls. A pruning saw or a specialized snow saw works best. Cut the blocks into 6 to 12-inch squares. Blocks must withstand being pried loose horizontally. To strengthen blocks further, allow them to sit in the wind.

The first layer of snow blocks requires at least one person to work inside the igloo while the other person places the blocks around the perimeter. The person on the inside must work to fill in any cracks with snow and ensure that all blocks sit flush against each other.

Starting with the second layer, the blocks must be cut at a slant -- beveled -- at the bottom to let others stack on top of them. The person inside works to make sure no blocks topple over, but after three blocks or more are placed side-by-side, they should stand on their own. The igloo's top should require no more than one snow block.

When the igloo's structure is complete, dig a tunnel from the outside to the igloo's interior. (Think of a rabbit's hole.) Cut several air vents into the igloo's walls.