system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can people have fires inside igloos without them melting through the ice?

Edit: Thanks for the awards! First time i've ever received any at all!
gpt
What happens is the rough inside later of the igloo melts a little bit at first but the super cold ice behind it which is being kept cold by the outside temperatures freezes it again in to a smooth crust. Because there's now less surface area the warm inside air is less effective at melting the surrounding ice.

So basically it's a constant battle between the fire inside warming up the air and the ice and cold air keeping the structure frozen, and the achieve a balance at some point.