Note: In the Inuit language, “igloo” can refer to any sort of house, not just a winter snow house. However, in English—and other languages—an igloo specifically means a snow house, particularly the type constructed by the Inuit peoples of Canada, Greenland, and Alaska; this is what I mean by “igloo” in this post.
In “Cold Welcome,” Cody discovers, in a most unlikely place, the elusive warmth that has evaded him for so long. The wintry igloo he builds with his long-forgotten nephew becomes a catalyst in rediscovering precious familial connections. Though an igloo is an ice-cold snow house on the outside, the interior can be significantly warmer—both physically and emotionally. Let’s take a look at this unique dwelling, which has withstood the test of time in some of the most forbidding places on the planet.
The interior of an igloo stays warmer than the outside thanks to three mechanisms: radiation, convection, and insulation. In the process of radiation, the people inside radiate heat from their bodies, acting as an internal heat source within the igloo. Next, this warm air, which is a fluid, gradually moves around the igloo by convection, circulating warmer air upward and cooler air downward, helping distribute the heat.
Then there’s insulation. Ice’s thermal conductivity, like that of air, is low; it stops heat from being transferred into the surroundings. The snow’s ice and still air trapped within are highly effective insulators, creating a barrier between the cold outside and the relatively warm interior.
Fresh snow is up to 95 percent trapped air. Ice, on the other hand, is very dense and is an excellent wind breaker. Since the super-dense ice is too heavy to lift to construct the igloo, the intrepid igloo builder uses snow that hits the sweet spot: dense, but not too dense. So the igloo blocks that are chosen have more air pockets (i.e., air trapped among tiny crystals) than a solid block of ice. Since the air cannot easily circulate inside this snow, heat gets trapped inside the igloo.
When snowflakes fall onto the roof of an igloo, they melt and refreeze, providing a replacement layer of insulation and transforming the snow blocks into an icy, well-fortified, domed refuge. This dome’s cross section is a catenary arch, which is a highly stable shape. Now the igloo will even withstand a feisty polar bear who fancies it as his trampoline!
The interior of an igloo is a quiet, calming environment; snow is a natural insulator of sound and heat. In my story, Cody and Logan are able to connect inside the igloo free of outside distractions. Though still cold, inside it is significantly warmer than it is outside. Hot cocoa and colorful stories help to keep them cozy. And, since they have carved the igloo in multiple layers, they can hang out on the upper sleeping platform, as warm air rises.
Inside the igloo, the snow does melt somewhat, but the water doesn’t drip because the dome’s roof is curved. Instead, it gradually soaks into the blocks. Later, once summertime brings warmer temperatures, the igloo will melt away.
But warm memories from that time in their igloo will remain with Cody and Logan long after the snow has melted.
Sources:
- “How an Igloo Keeps You Warm,” YouTube video with Joe Hanson, c. January, 2017
- Scott Welch on Quora, answers “People who’ve built and slept in igloos, what’s it actually like?” updated, 2021
- “Why an Igloo Doesn’t Melt Inside,” in Scientific Humans, copyright 2023
- Transun, “How Does an Igloo Work?”