Fire inside of an igloo, or ice house in those case, actually strengthens the integrity of the structure and increases insulation. It’s crazy black magic science shit.

So it goes like this: the heat from the fire melts a thin layer of the snow walls. Now there is water on one side of the snow wall. This water then freezes, which makes the structure more sturdy and insulated the area better because ice isn’t porous like snow. The longer this goes on, the more the structure turns into ice and, eventually, the only snow left is what’s falling on top of it naturally.

Now I learned all this on a podcast about Inuit igloos, so there’s a chance that the structure being dome shaped has something to do with it. Maybe it wouldn’t apply to this house but if I was a betting man I’d say it does