BOD said:
Ignorant question but here goes:
All the igloos I've seen in my picture book, film, TV and my have neat rounded access tunnels but yours has a pointy apex.
Any reason or just builders creativity?
I'm not certain, though I suspect snowfall has a lot to do with it.
look at the difference between the iglu the first day it was built, the night shot for example, and a couple of days later when I'm standing on top of it.
The difference is one night of light snow fall, which changed the shape of the exterior from a multifaceted surface to a smooth round dome.
This snowfall has the effect of changing the outer surface of the entrance tunnel from a roofed apex to a rounded half pipe as the snow collects, the interior is smoothed off by repeatedly crawling in and out of it, the back of the crawling occupant gently eroding and polishing the interior surface and thus rounding it off.
That would be my explanation anyway, I see no reason why you would build a rounded tunnel to begin with, it would require an additional roofing block for each block in length, it would be less stable and there would be no benefit to the design.
On a slightly different but related subject, Mors and myself did some research on the concept of putting an 'air hole' in the roof of quinzees as described in the majority of 'survival manuals', our reasoning being that the Inuit didnt normally have 'air holes' in the roof of their iglus because ample fresh came in though the doorway which was traditionally left open and a 'air hole' in the roof would just let the bubble of warm air near the roof escape though it, defeating the whole object of the domed shelter with a low entrance and a high sleeping platform; So it seems nonsensical to have an air hole in the roof of a quinzee which works on the same principle.
We concluded that provided you didnt block up the doorway, which you shouldnt do in a quinzee with a raised sleeping platform anyway, there was more than enough air circulation to remove carbon dioxide and an 'air hole' in the roof was counter productive, it just provided a hole for the warm air to escape and contrary to what many poorly researched manuals might suggest carbon dioxide does not 'rise to the roof and exit though the hole' anyway!
Air holes should therefore probably just be left to 'snow holes' in which it is common practice to bock up the entrance to reduce draft.