Lone Trek - Hiking Alaska Solo: November 2009

I've always wanted to build a "real" igloo, but never had the right snow conditions. You ideally want snow that has been solidly packed by wind, to a depth of two feet or so. That depth of wind-packed snow occurs in the arctic, but not too often in Anchorage, Alaska, where I live.

So I decided to see if I could pack the snow well enough, myself.

The short answer - Yes!!

(But it sure is a LOT of work!)

Below are a few pictures of my endeavor.

As usual, just click on the small pics for an expanded view.

Before retiring for the night.

Not having much wind-packed snow here, the first order of business is to pile up the snow and pack it down. I shoveled it into a row, and then stomped up and down the row. Then, I piled on more snow, stomped, & tamped with my shovel.

I tried making mounds of snow, at first, but found it's far more efficient to pack the snow into a long row, so you can cut blocks - ideally - about 3 feet wide by 1.5 feet high by 6 inches thick.

After the packed snow has hardened (after a minimum of one hour) it can be sawed into blocks.

Each of my blocks weighed about 15-20 lbs, on average, I'd guess.

Yes, that's a snow saw. (It's made by Black Diamond - I got it at REI.) The handle is too small, making it very awkward to use. But it works, and is very compact & light weight.

All this snow was light and fluffy to begin with. Try an experiment the next time you encounter light and fluffy snow. Stomp on an area and then come back an hour later. You will find your stomped-on light-and-fluffy snow quite hard.

After building up the first few courses, the blocks for all the remaining courses need to be sawed, carried inside, and neatly arranged within (if one person is doing everything).

If there is more than one person, the person on the outside could cut & carry the blocks, handing them over the wall. That might save a row or two of stockpiling blocks inside.

I tried to carve the sides of the blocks nearly perpendicular to the faces, and before placing them, cut the top off the course below to match.

Stockpiling the interior space with snow blocks.

Interestingly, counter to intuition and to what I've heard, I found the first three or four courses much more difficult than the last. Isn't that bizarre?

I think it's because the first courses just lean, but don't have much to lean on. But blocks in the top courses lean firmly against each other, propping each other up. That's my theory, anyway.

Anyway, the top was the least challenging, technically. My arms got tired working overhead, but the higher up, the more secure was each block. As you go up, the higher blocks tend more to wedge in between their neighbors. Cool, huh?

The cap - and all the blocks for that matter - were placed from the inside. I cut the door from the inside when the whole thing was complete.

There are square floorplans that would perfectly suffice to support a stable arched structure. The problem with those shapes is that there is no intermediate structure which is also stable.

That is, a squared dome can be perfectly stable upon completion, but not until then, so you can't build one without some kind of scaffolding.

In this light, something really incredible about the Inuit's igloo is that they devised a way to build a dome structure which is stable even during construction. I think the dome is the only shape that suffices for that requirement.

Woe is you if you run out of blocks before finishing construction. You will then have to cut your entryway into the unfinished wall (risking collapse) and then cut and shove your remaining blocks through that tiny hole (lotsa work).

After stockpiling all the blocks you need, then you step inside and work from within until complete. You carve the last few blocks close to the shape of the hole above, and then lift them through the hole and lower them into place, carving them into their final shape as you settle them into their spot.

My first igloo, completed.

This was WAY bigger than necessary for one person. About 10-12 feet in outside diameter at the base, and 5.5 feet high.

Two people would have found it very spacious. Three or four could have slept in it, though that would have been a bit cramped.

A more expertly constructed igloo would have retained the heat better, bringing the internal temperature to well above freezing. That causes the interior to melt a bit, which then immediately re-freezes because it's in contact with the snow.

So you end up with a thin layer of ice lining the interior, and cementing all the blocks together. Between this and windblown mortar filling in the crevices from the outside, an igloo supposedly becomes strong enough to climb on (though for all the work it takes to build, I'd rather not give it such a test).

If I'd made mine smaller, or had more people with me (to generate more heat) the interior may have melted. But alas, the interior is not iced up at all, so I think it lacks strength. Also, I think I built the walls with too little curvature at about mid-level. Furthermore, some of my blocks I placed so as to bridge a corner, which led to at least three blocks at level-3 fracturing and settling - almost caving in.

With that combination of factors, I'm not expecting it to last long this winter.

At my level of expertise, this would NOT be a good option for an emergency shelter, because it takes WAY too long. This took me 9.5 hours, total. Most of that time was packing and cutting the snow blocks.

For me, a better option for an emergency shelter would be to pile up snow and then dig out the interior. This kind of structure is called a "Quinzhee". I've built these several times over the years. It only takes a couple hours, but isn't nearly as roomy. Also, they make me more wary of collapse, because the walls being about one foot thick are very heavy. But if the igloo above collapsed on me, I'm quite certain I could have just stood up (growling and yelling).

Another option: dig a snow cave into a big drift. But this requires a big drift, of course.

With all these options, including the igloo, you have to be careful to ensure ventilation. For my igloo, I didn't seal the door all the way, and poked a ventilation hole just above the door, and another one in the roof.

Good night, all. Aren't the stars beautiful?

It was quite a bit warmer inside than outside. Outside was around 20 deg F. Inside was around 25-30 deg F, and of course, no wind. Outside was howling wind.

I kept waking up during the night, wondering if my amateur igloo was going to collapse. Thankfully, it never did. Yay!

At fist, I was only adequately warm, and the first couple hours could not get my feet to warm up. After 2:00 AM, all was toasty. :-)

The walls are thin enough in this igloo that if it collapsed, I think the weight on me would not be at all challenging to crawl out of. What I most worried about was finding, digging out, and getting on my gear before my hands and/or feet got frost-bit or I became hypothermic. I gathered all my gear in one spot for that eventuality, and planned to work quickly to get dressed.

For this experiment, I was only 20 minutes walk from my car, so I knew that all I had to do was get on my boots & gloves, and could leave everything else buried & head home. Then, I'd come back the next day & dig out all my stuff. In a real back-country adventure, of course, that wouldn't be an option, which is why I didn't build my first igloo very far from the road.