2.Mark the thickness of the walls. Now, gather about 20 to 30 straight, 1-foot-long sticks. Remove any side branches. Travel around the shelter, and push the sticks straight into the dome (perpendicular to the surface) in random places so that the ends sit flush with the surface. These sticks are going to be your guide as you dig out your shelter.

3.Dig out the shelter. Now comes the fun part. Determine where your entrance is going to be; this entrance should be a good 2 to 3 feet above solid ground and as small as possible, though big enough for you to fit through comfortably and start digging.

Dig in a straight direction toward the center of your dome. If you packed the snow well and it was given enough time to solidify, you should encounter no small collapses while digging.

4.Enlarge your dome. You should find your equipment toward the center. Carefully drag it out through the entrance. Keep digging carefully, slowly enlarging your dome until you reach the tips of the sticks you pushed into the dome. These sticks are an indicator you have reached your target wall thickness of 1 foot. If the day is bright, you may find that as your wall becomes thinner, more blue light will filter in through your walls. This may be a bit unsettling, as it can seem you’ve nearly dug through the wall, but do not worry. This is why we pushed the twigs into the wall earlier.

5.Finish the ceiling. Create an even dome by smoothing out the surface with your hands so that any melted water will not drip from it.

Adding an Entrance

1.Now that the dome is complete, place a backpack or other gear up in front of the entrance, blocking it. Pile another big heap of snow in front of the entrance. This pile should stick out from your shelter by about 4 to 5 feet, have a width of about 5 feet and be 1 foot higher than your original entrance, about 6 feet from ground level. You must ensure that this pile is patted down well and forms a seamless bond with the original dome. Once again, collect some 1-foot-long sticks and push them into the sides and roof of the entrance tunnel. This time, the sticks are not intended as a target to reach so much as a way to stop you from accidentally breaching the walls when digging out the entrance.

2.Dig out the entrance. In front of your heap of snow, dig down to solid ground level, or to 2 to 3 feet below the level of your shelter. Make this pit nice and wide, as you’ll need plenty of space. The reason for the pit is that cold air sinks while warm air rises. So, by having your main shelter higher than ground level or by creating a big pit outside your shelter, you’ll encourage the cold air from inside your shelter to move there, while the warm air will be retained inside the shelter.

3.Open up the entrance tunnel. After digging this pit (or if you’re already at ground level), create a small entrance (with a saw if you have one) by digging at ground level into your entrance, working your way up to the hollow you created earlier. When you reach your backpack or other gear that you used to block the entrance, you can carefully remove it, which should open the entrance tunnel up into the main shelter. Digging here is probably the trickiest part as you’re trying to keep the entrance small while digging up a slope. Ideally, the ceiling of your entrance tunnel right at the entrance should be lower than the floor level of the main shelter. You can further improve upon the entrance by building a U-shaped snow wall around the entrance to deflect wind, leaving enough room to get in and out.

Insulating the Shelter

1.Gather insulation. Now that the shelter is built, you are ready to move in. Gather as much insulation as possible to use as bedding, such as sleeping mats, debris, sleeping bags, spare clothes, etc., applying the principles discussed on page 10 in “Shelter Fundamentals.” If you wish, you can shape the snow inside into more comfortable seats, shelves and whatever else you need. Just be sure not to make the wall thinner than the foot indicated by the twigs inserted into the walls.

2.While digging, you probably already noticed that it was quite a bit warmer inside the shelter than outside. If the shelter is small enough, mere body heat may be enough to heat it. Small candles or tea lights can also be used to raise the temperature somewhat. The temperature of the shelter should never be higher than freezing point, but compared to the temperature outside, it should feel like a good improvement. At a temperature of about 30°F, you will probably find that your clothes or sleeping bag are enough to keep you warm and comfortable. Having built such a shelter in –50°F in the Yukon, I can attest that the temperature inside the shelter felt positively balmy and that it was comfortable and cozy enough to spend an extended length of time in!

In the picture below, I have dug away one side in an attempt to show the size better and clarify the different floor levels with the entrance tunnel angling up toward the main shelter.

Again, just like with the other shelters covered, the descriptions are only intended to teach you the underlying principles. Once understood, you should not feel limited by the designs in this book. In the case of snow shelters, for instance, other options may be to simply dig a 3-feet deep hole horizontally into a snowdrift or slope, before digging upward to create a pod big enough for you to sit up or even lie in. Excavated snow can be heaped onto the outside to give you a larger shelter. Another option is to dig a pit, which is then covered by evergreen branches and snow or even just blocks of snow, much like the subterranean shelter we covered earlier.

There are a few considerations to take into account when using a snow shelter. It is very important to not close off the shelter entirely in order to refresh the air. In a snowstorm, for instance, regularly checking the entrance, or even poking an additional hole through the ceiling is very important. I have heard it said that ice formed due to condensation on the inside of the shelter should be scraped away regularly to prevent a decrease in fresh air-circulation, but I have never done so and noticed no adverse effects. In fact, snow shelters, such as igloos are purposefully allowed to build up an ice-layer on the inside as a way to increase structural strength. In any case, feeling drowsy and confused or getting a headache, may be signs that carbon monoxide is building up and more ventilation is needed. In conditions where the weather hovers close to freezing, the benefit of shelter is reduced to only providing shelter from wind (and precipitation); however, the risk is a lot higher, as thawing may cause your shelter to become unstable and collapse.