This is an Instructable showing the steps I used to build this Igloo...
Step 1: Preparing a base
I started by finding a spot in the yard where I had a snow drift that was about 2 1/2 feet deep. then I shoveled a clearing a little larger than I wanted the base of the igloo to be. I left about 6 inces of snow on the ground for a floor.
Step 2: Construction begins
I used a 15 x 12 x 7 " plastic bin to form my snow bricks.Holes were drilled in the bottom of the bin to allow the blocks to release from the mold. In order for the blocks to be formed. I used a shovel to fill the mold quickly then screeded off the snow that remained sticking out of the mold with the shovel. I got a pretty good pace going and could build about 4 blocks per minute. The snow conditions need to be just right, packable but not too wet. Temperatures in the mid 30's F work the best. I used a tow strap hooked around a center pole to act as a compass to lay out the first row of blocks in a perfect circle.
Step 3: Building my way up
I continued stacking blocks row upon row working my way higher, leaving an opening where I wanted the entrance to be. I used a small crosscut saw to cut angles on the blocks so they fit together as they followed the circular layout. Snow is packed in any voids by hand. Once I got up about 3 rows I started to allow each additional row of blocks to overhang the previous row, to the inside of the igloo. Snow was then packed under the overhanging block .
Step 4: Building the Entrance
I stacked up the sidewalls of the entrance and tied them into the side walls of the igloo with an interlaced pattern of the blocks. I left the roof off of the entrance until the end of the build, this way I could move easily in and out of the igloo carrying blocks as I worked on the roof of the igloo.