On winter adventures, building a snow cave or igloo comes up regularly. In emergencies they are known as the last line of shelter against a cold winter night. But can a snow cave also serve as an everyday tent? The short answer is yes, provided you set aside one to two hours to build one.
Staying safe on a winter adventure
A snow cave is no substitute for your equipment. Heading out in winter conditions can be dangerous and demands careful planning and experience. Do not use this description as a replacement for a hut or a tent. We advise against using snow caves unless you are under the supervision of experienced guides.
The different types of snow shelter
In an emergency there are three situations to choose from:
- A slope with enough snow: the cave
- Flat ground with enough snow: the tunnel
- Not enough snow: the mound
As a base camp
Here we prioritise comfort and living space. This build needs sufficient snow depth and costs more energy. The result, though, is a genuinely pleasant place to stay. The starting point is a tunnel or a trench.
The igloo
Choose this option when you have to work with ice or hard snow and digging is not an option, or simply for the pleasure of it, because an igloo looks superb. This shape does have the steepest learning curve.
How comfortable a snow cave really is
When you think of a snow cave, warmth and comfort are not the first things that come to mind. Yet that is exactly what a snow cave offers.
Snow is an excellent insulator, which makes for a very quiet night. A well built snow cave is at least as warm as a tent and can even get too warm.
How do you make your snow cave comfortable?
Warm air rises and heats the snow on the ceiling, which melts and forms drips. Those drips can soak you completely. You prevent that easily by smoothing the ceiling and providing a ventilation hole.
Our experience shows that sleep and food determine the quality of the whole experience. To sleep well you do not want to slide off your mat at night or work around a bump underneath it. Make sure you can lie flat along your whole body length. A snow cave can quickly beat a tent for comfort.
To widen your comfort zone gradually, start with a half open snow cave in good weather, or one you cover with your pulk instead of with snow. Going straight to lying with your head two metres under the snow is not a sensible first experience.
The coldest air is heavy and sinks to the lowest point around you. So make sure your bed is not at that lowest point. By digging a cold trap you give that cold air somewhere to settle.
That is literally a pit at the entrance of your shelter. Comfort is something you create yourself. You will be amazed at what you can achieve with persistence and clear thinking. Allow some extra room to lie down, for instance: at first it is easy to underestimate how much space your mat and sleeping bag take up. The same goes for a level floor, where working precisely pays off.
How the strength of snow changes through the day
This information must not be used to assess avalanche risk or other hazards.
Both wet and dry snow harden as the temperature drops. You work with the snow when it is at its warmest and therefore weakest. As the night goes on, your structure only gets stronger.
What we learned ourselves
In our search for the limits of snow caves we managed to collapse one exactly once. That happened with a roof barely 5 to 10 centimetres thick across a span of 1.2 metres. At that thickness the snow weighs so little that you barely notice anything happening, and suddenly you are standing outside. The collapse occurred while we were thinning the roof by scraping snow off the ceiling.
With a minimum roof thickness of 20 centimetres and using only rounded shapes, we can always stand on the roof in snowshoes. In the morning, after a night in a snow cave, we often enjoy jumping on the roof to test its strength.
Building a snow cave
Choosing a location
In a snowy landscape some places hold more snow, while elsewhere there are obstacles or too little snow. Use a probe or a long, thin stick to find the best spot. That lets you measure the depth and detect rocks, saplings or other obstacles. It stops you from digging where there is not enough room for your structure.
Digging
The most important thing is to manage your sweat. So swap regularly between digging and resting: one person digs while the other recovers. That way it takes roughly two hours to build a shelter for two.
Try to work in blocks you can throw out of the cave. Whoever is outside can stack those blocks or push them aside.
Cutting blocks
To roof your tunnel, narrow your entrance or build a structure, you use blocks of snow or ice. Look for a good ratio between thickness, width and length. Around 10 by 40 by 60 centimetres is ideal for handling easily. What is possible depends on the type of snow, of course.
Ventilation hole
First smooth the surfaces, so drips cannot form on rough patches. Then make a hole to the outside to let the warm air at the top escape. Skip that and you will get wet during the night, guaranteed.
With a thin roof a branch or walking pole is enough to make that hole. If the hardness or thickness of your roof is a problem, you can use a pot of boiling water as a drill. Pour the boiling water on the spot where you want the hole. On average a litre of boiling water penetrates about a metre of snow. Make sure nobody is underneath the shelter and that nobody is exposed to the boiling water.
Preventing collapse
Keep your roof at least 20 centimetres thick and use rounded shapes for the walls and ceiling. After sunset the surroundings cool quickly, which makes your snow cave safer. So always stick to the principle of minimum roof thickness and rounded construction to avoid any risk of collapse.
Challenge yourself in the wilderness of the far north: build your own snow cave, experience the silence of endless snowfields and start an unforgettable winter adventure.