After building my latest snow fort, I came to the realization that there was a method to my madness. When building I use a snow scale method I have grown fond of, this involves packing the wet snow within an arms radius into a scale like brick. Snow scale describes the way the snow brick has a hard external top layer with a soft inside layer, this also causes it to have a convex form as well. This is important as the convex shape allows for a strong dome shape. The full design uses two layers of scales for walls with a simple arch for a door. After these are built you use a keystone (handful of snow) to prop two scales leaning inwards together and go from there until the next dome layer is finished, then you finish with a final curved in layer held up by a few scales as a final keystone.
The interesting thing about this building method is how it very closely resembles to the structure of Geodesic domes because of the way scales are interlocked with a series of keystones. This distributes the force of the snow down the walls of the structure. This is why I have been able to create forts with a radius well over five feet, with walls that are only seven or eight inches thick.
