Shelter is critical to maintaining body heat. That’s why building or setting up a shelter is such an important part of wilderness survival. For the most part, we think of wood and brush when we’re thinking of this, although the debris shelter uses a leaves and other debris off the forest floor.
But what do you do when you don’t have trees to use? There are parts of the country where trees are rather rare. But that doesn’t eliminate the need for shelter. It just means that other means and materials need to be utilized. That’s why it’s so important to have a tent or tarp in your pack, so that you always have shelter available, even in areas where there are no trees.
Another old remedy for this problem is to use snow. You’ve probably heard of the Eskimos making their homes out of blocks of snow, which later turn to ice. But that’s not something that you and I are ready to undertake. Even so, there is one sort of snow shelter that we should keep in our bag of tricks; that’s the snow cave. Snow caves are useful in winter survival situations where it is extremely cold, as the temperature inside a properly built snow cave won’t drop below 32°F.
Snow caves are not all that hard to build, but you need a deep snowbank to build it in. the overall height of that snowbank needs to be at least six feet, although a couple more heat would be good. Most snowbanks form so that the vertical surface is downwind, which is perfect for your needs.
The floor of the snow cave isn’t at ground level. Rather, it needs to be high enough off the ground so that it is above the top of the doorway. This is critical! Remember elementary school science? Since heat rises and cold drops, the cold ambient air won’t come into the snow cave, if the floor is above the level of the top of the door.
To make the snow cave, start by digging the tunnel from ground level. This needs to angle upwards at about 45 degrees, to the level of the cave itself. It also needs to be big enough for you to crawl through.
When you get to the level of the cave, pack the snow up, down and sideways, making an area large enough to lie down in. You’re going to be better off packing the snow, than removing it; but if the snow bank is already somewhat packed, you may need to pull some of the snow out the door.
If you make a mistake, and end up with the floor of the snow cave lower than the top of the doorway, you can try adding snow to the top of the doorway or bringing more snow into the cave, raising the floor; but getting that relationship right is critical.
Some people will cut a door to fit into the opening; but that is not required. Once completed, crawl inside and bring your gear with you. Your body heat will keep the area inside at 32°F, at which you can survive. Lighting a candle inside will raise the temperature a couple more degrees, say to 35°F, but you can’t really go any higher than that, without melting the roof of the cave.
While this isn’t the most comfortable of shelters, it can actually be warmer than anything else you can construct, if the ambient air temperature drops below freezing. It’s hard to heat most shelters in that situation, unless they are really well built. But the snow cave will naturally maintain its temperature at freezing, without going lower.