Igloo

Is it to avoid snows being collected on the Igloos ?

As we all know that Igloos are made of snow and so it needs strong foundation and for this reason usually they are dome shaped for strength, and in the regions where we find igloos, there are strong winds because of the open space, so dome shapes allow the winds to go around. Round walls are much stronger. Also they are round for proper distribution of heat, and so that the smoke from the fire can go out from roof without making any mess inside the igloo which usually has limited space.