Igloos

by Dennis Randall

What parent or child hasn't looked at a yard full of snow and thought, at one time or another, "Wouldn't it be neat to build an igloo?"

Before we jump into the "how-to" of igloo building, here's a little history. The igloo is a brilliant shelter solution, ideally suited to a region where more traditional building materials were virtually nonexistent. No trees grow in the land of ice and snow above the arctic circle. Rocks and stones that might otherwise serve as construction material are buried under mountains of snow or lie out of reach beneath the ocean and ice flows.

Contrary to popular myth, the native peoples of the far north didn't live in the same igloo all year around. Survival in the far north depended upon hunting and successful hunting requires that you go where game can be found. The igloo was primarily used as a temporary hunting shelter. One of the beauties of an igloo is that a hunter didn't have to be weighted down with carrying that night's shelter on his back. One could be created in an hour or less with a few simple tools and the one material in plentiful supply. Snow.

What you'll need to build your igloo
 

• Patience. Lots of it. Nothing is as easy as it looks ;-)
• Plenty of well packed snow at least 12 inches deep (the deeper, the better).
• A snow saw for cutting snow blocks (a regular carpenter's saw will do).
• Small straight edge camp shovel (flat).
• Water proof mittens or gloves.

Step I: The circle stomp

The first step is the easiest (isn't that always the case?). Find a level spot to construct your igloo and  start by stomping out a circle in the snow for your foundation.  When you've finished construction, the stomped area will be the igloo's floor.

Step II: Playing with blocks

Using your camp shovel, dig into the face of your snow pile and clear an area where you can begin to quarry blocks of snow for your igloo. Next, using your saw, cut away blocks of snow. The building blocks can be any size you want -- as long as you can carry them to your building site without breaking them. Igloo experts suggest that the ideal block should be about 3ft. long by 15 in. high by 8 in deep.

Step III: Around and around

Lay your snow blocks at the outside edge of your stomped area. You'll want each block to be higher at the end furthermost away from the starting point of construction. The idea here is to create a long sloping spiral, like the thread on a screw. Each new block will rest against an old block as your igloo's walls winds its way to the top. Smooth loose snow into any gaps between the blocks as you go.

Don't worry about cutting a space for the door. That's the last step in the process.

The trick is to place the blocks so that they slope inward toward the circle's center. Don't make the angle too steep or they'll fall over. Of course, if you don't tilt them enough you'll end up constructing a tall cylinder instead of a half dome.

Step IV: Capping off

If everything has gone according to plan, the last few blocks will be nearly parallel to the ground. Don't worry, gravity will keep them in place. The trick here is to make the final blocks slightly larger that the hole they'll cover.  Use your snow saw to trim them to the final fit.  A slight keystone effect __/ will prevent blocks from falling through the opening to the floor.

Now that you've trapped yourself inside, it's time to dig the door. Carefully dig a small tunnel under the wall to create an exit. If the snow isn't deep enough you'll have to cut into the wall itself. Keep the opening as small as possible to insure that you don't collapse your finished igloo.

Step V: Remember to breathe

IMPORTANT: You MUST cut ventilation holes in your igloo! If you don't, carbon dioxide (or carbon monoxide if you're using a candle or oil burning lamp) can build to lethal levels and you could end up  dead. Not nice. At minimum, in addition to your door you'll need several small vent holes at the top of your igloo.
 

Step VI: Enjoy!

How can a house made of ice and snow keep you warm? The igloo's secret to is that snow and ice, in addition to blocking the chilling effects of the wind, are excellent insulators and work well to trap and hold the body heat of the occupants.

You are your igloo's furnace. Between your body heat and the heat of one or two SMALL oil lamp, the interior temperature of an igloo can rise to the relatively toasty temperature range of 50 to 55 °F. Not exactly shot sleeve weather but better than freezing to death. ;-)

When you are inside your igloo, the heat from your body will cause the inward facing surface of your snow blocks to start to melt. Don't worry, the melting snowflakes quickly turn to ice because they are in direct contact with the snow behind the wall. This melting and re-freezing of the surface produces an air tight seal -- which is why the vent holes discussed earlier are critical.

Depending on the amount of abuse you subject your ice house to and the outside air temperature, your igloo should last for a few days to several weeks. In the end, an igloo's fate is the same as your backyard snow man. They melt away in the ultimate form of natural urban renewal.

More on: Fighting the Winter Blues