IGLOO BUILDING – How to Construct a Snow Shelter

September 27th, 2011

Snow architecture | Alf Alderson

Temperatures inside an igloo can be as much as 50C warmer than the outside air temperature – with that in mind Alf Alderson tells you how to build one for next time you’re stuck in a blizzard.

Checking Snow for Depth

1. First choose a site that has deep enough snow (at least a metre) and is not prone to natural hazards such as avalanches. An igloo big enough for two/three people should have a diameter of about 250cm.

Preparing Site

2. Snow needs to be firm to be cut into solid blocks that can be built into an igloo, so you’ll need to stamp around the site in your boots, skis or snowshoes for up to 20 minutes to pack it down densely enough. And you can’t start cutting blocks immediately – after ‘boot packing’ the snow must then be left to ‘set’ for an hour or so, which gives you a good excuse to get out your stove and brew up.

Tools of the Trade

3. The two essential tools for any igloo builder are a snow saw and a shovel. Make a ‘quarry’ by digging two trenches in the boot-packed snow, smoothing off the sides. Cut the building blocks from these trenches – ideally they should be the width of the saw handle, the depth of the saw blade and the length of the entire saw.

Cutting blocks

4. Cut the back first, then the side, and finally along the bottom, in smooth, clean strokes – you may need to gently prise the blocks away from the surrounding snow as you don’t want to break them. Those that do break should be saved for filling gaps etc.

Laying First Blocks

5. The first two blocks should be cut into uneven halves with a slightly angled slope on the top side. Then cut the rest of your blocks to a standard rectangular shape and lay them around the circle you’ve marked out for your igloo. Hold the blocks firmly in place until they’re self-supporting, and they should lean inwards at quite a steep angle – don’t worry about them falling over (one or two will inevitably do so but they can be re-sited), you’ll be surprised at just how much they’ll lean without toppling. Cut one longer block to mark the space where the door will go.

Wall Goes Up

6. When you start on the second row you’ll initially be laying the blocks on top of the first two blocks you cut with an angled upper slope – this ensures your igloo’s wall spirals upwards as it increases in height. Each row should lean inwards at a steeper angle than the one below. Gaps between blocks can be easily filled with snow.

Making an Entrance

7. Dig out the floor of the igloo to give yourself more head room, and at the same time make the door – this too involves digging down to create a tunnel in the snow, with the entrance emerging outside the wall of the igloo. When you’re sleeping in the igloo cold air will sink down and be trapped in this space.

Last Few Blocks/Preparing to Lay Final Blocks/Skylight

8. Ensure you keep some snow blocks inside the igloo to cap the roof – ideally a partner on the outside can help with this.

Smoothing the Walls

9. When the igloo is finished, crawl inside and build sleeping shelves using the snow you dug out of the floor – this ensure you sleep above the cold air welling up in the lower points of the igloo. Also smooth the walls to prevent any melting snow dripping off protrusions in the wall.

On the Roof

10. A properly built igloo can take the weight of a man on the roof, will stay up all winter and will withstand hurricane force winds.

Al fresco dining

11. If there are a few of you, spare or broken blocks (there will be plenty of these if you’re a novice igloo builder) can be used to build a wall and seats for a dining area – and you’re sure to be ready for a good dinner after your exertions.

In my igloo/Ready for bed

12. Igloos are obviously much warmer than sleeping outside on a sub-zero Arctic night, but you’ll still need a very good sleeping bag and sleeping mat to stay warm over. A few tea lights provide lovely lighting and don’t cause excessive melting. A nip of Scotch is also very welcome just afore retiring…

Morning, Morning Igloo Village Morning

13. Waking up in an igloo is a great experience – the diffuse light seeping through the walls is a far better alarm call than any beeping alarm clock, and if the sun is shining the peppermint fresh air and wilderness views when you emerge from your cosy (ish) home provide a fine start to the day.

Home Breaker

14. For safety reasons when leaving your igloo for the last time you should destroy it – if heavy snowfall covers it other travellers may inadvertently fall through the roof, or someone may be tempted to use an old igloo which could collapse on them. You’ll probably be surprised just how much effort it takes.

West Coast Adventures offer various igloo building courses close to Vancouver, BC