HOW TO MAKE AN IGLOO:   PICK A SPOT       You should build your igloo on a level surface where the snow is at least 3 feet deep. There should be enough hard snow for your igloo, if the surface snow is powdery there's probably hard packed snow a bit deeper. Large bumps on the surface of the snow it usually means that there is a large object below the snow such as a boulder or a large stomp, they can get in the way so it's better to pick as flat a spot as possible. Don't make your igloo bigger than it needs to be. Mark out in the snow where you plan to have the wall of your igloo.           CUT BLOCKS    Cut out blocks from the area which will be the inside of the igloo. The lower blocks should be about 1 foot thick, 3 feet long and 1.5 feet high, the higher blocks should be about 6 inches thick, 2 feet long, and 1 foot high. If you size the blocks as I have said above you will need approximately the following number of blocks: Sleeping 1 person, 6 feet inner diameter: 30 blocks Sleeping 2 people, 7 feet inner diameter: 40 blocks Sleeping 3-4 people, 9 feet inner diameter: 60 blocks Don't worry if you think you'll have trouble fitting, once the igloo is finished you can carve out a bit of space for your feet from the inner wall. The hole resulting from your cutting will be the floor in the igloo so you want a sleeping area for each person as high up as possible, a general purpose area that should be a bit lower to allow for mobility, and a deep entrance hole that extends outside of the igloo. The entrance hole should be as narrow as possible while still allowing you to get in and out without too much discomfort. The deep entrance hole will absorb the cold air and release it to the outside while the warm air will rise and stay trapped inside the dome.            BUILD A SPIRAL CIRCLE     Place your largest and widest blocks in a circle around the hole where you have been cutting out your blocks, the blocks should be tilted in towards the center. Start with the block that goes on top of the entrance hole, the whole entrance hole must be traversed by one single block with plenty of support on both sides. Cut the blocks so they form a spiral, make sure that the block covering the entrance hole is the largest block.          BUILD WALL    Add blocks to the wall until you only have a small opening in the roof. Before you get to the point that it's hard to get in and out of the dome move any blocks not yet used to the inside of the dome so you can put them all up in one sweep from the inside.         TOP PIECE     When all the blocks are in place cut the final top piece to the right size. If you can wiggle it out from the inside and lower it down into position that's great, but if your hole is very circular this won't be possible, you'll have to put the block on top of the dome from the outside and then lower it down from the inside.        FINISHING    Fill any cracks with snow. Make a little doorway over the entrance to keep snow out. You have to make at least one air hole in the roof to ensure proper ventilation. Without good ventilation you could run out of oxygen, very dangerous. Smoothen the inside of the dome to prevent water dripping.   Your igloo is now ready to be lived in, check your air hole periodically to make sure it's not blocked. If you've done everything right you will be quite comfortable.