Snow caves can be an appealing way to shelter from the cold and are used by humans all over the world. They are popular with mountaineers and winter survivalists but are also be appealing for anyone who loves to explore nature. I mean, what could be more fun than building a house out of snow?
Unfortunately, snow caves can be really dangerous to those not adequately prepared or who are inexperienced. Therefore, it is important to be aware of common pitfalls and how to avoid those risks.
This article outlines the seven most common dangers of snow caves, as well as steps you can take to prevent them.
1. Hypothermia from Digging the Snow Cave
The first thing you need to do is build your snow cave. This alone can cause problems.
Building a snow cave involves strenuous activity, including consolidating the snow by trampling it with skis or snowshoes, digging and moving snow, you are likely to start sweating a lot. In cold temperatures, this can quickly become dangerous, as sweat will cause you to lose body heat. In all survival conditions, it is important to remain dry.
You can avoid the dangers of hypothermia by taking regular breaks while building your snow cave. Therefore, make sure you start building in good time so that you are not rushed. Not only can this put your life in danger from sweating, but it can also lead you to take shortcuts on important structural safety features, which will be discussed in some of the other points.
Another important way to stay dry and therefore warm is to work in fewer layers, such as only your base layers and Gor-Tex layers. That means that fewer layers will become wet, making them easier to dry. You might even want to take them off afterward if you have spares with you.
2. Hypothermia While in the Snow Cave
Avoiding the risks of catching hypothermia while building the snow cave is not a guarantee of avoiding the cold. While snow caves are very good at insulating you from the elements, they need to be built correctly to have the best chance of doing this.
A snow cave relies on your body heat to warm it up. To avoid the warmth escaping, you will need to make sure that the sleeping area of your snow cave is substantially higher than the entrance make use of the fact that warm air rising. This will give you the best protection from the cold.
Additionally, since snow caves are still made out of very cold or frozen material, you also need to make sure you place an insulating layer between you and the snow below you to avoid the cold.
Cave-ins are one of the most common problems with snow caves. If your roof collapses on you, all your hard work will have been for nothing. You will immediately be compromised and exposed to the elements yet again.
Cave-ins can occur through several different problems:
- The roof is too thin – Your snow cave roof should be a minimum of 12 inches thick. Make sure the snowbank you are using is substantial enough to fit a snow cave. However, if the roof is too heavy, it may also become unstable. The best shape for the sleeping chamber of your snow cave is a dome shape. This gives the greatest stability to the roof.
- The snow is too wet – This is a major issue if the temperature is not low enough. Snow caves are only a suitable shelter if the conditions are well below freezing. In warmer conditions, a tent is much better.
- Something presses on top of the roof – This could either be caused by someone walking over it or something falling on it. To avoid this, make sure your snow cave is clearly marked around the area so that no one accidentally strolls across on it. Also, make sure you build your snow cave away from any unstable rock walls or damaged trees that might fall on you.
Avalanches can also cause cave-ins, but they can also cause a number of different issues and are worth mentioning on their own.
Any winter mountaineer or survivalist is likely aware of the dangers of avalanches to their activities in general, but even a substantial shelter does not mean you are safe.
Avalanches can cause you to become trapped by completely blocking the exit, as well as blocking your vent holes. This substantially increases the risk of carbon monoxide poisoning.
If you are sheltering while awaiting assistance, avalanches can also completely mask your location, making a successful recovery operation much less likely.
To avoid avalanches, be aware of the local conditions, check local avalanche forecasts and be aware of any slopes which are avalanche prone.
5. Carbon Monoxide Poisoning
Once you have taken all the preparations to make your snow cave as ready to sleep in, it is tempting to then start warming it up with a stove or fire.
This is really dangerous.
That is because stoves, fires, and even kerosene lamps produce carbon monoxide, which is also known as the silent killer. The worst part is that a build-up of carbon dioxide (CO2) will cause you to wake up gasping for air. When carbon monoxide has built-up, you usually will never wake up again.
Carbon monoxide kills quickly by causing edema in your brain or lungs. It can also cause dangerous delusions or brain damage before being fatal. So even if levels of carbon monoxide don’t reach levels that will kill you, it can still put you in significant danger by causing you to behave irrationally or becoming incapacitated.
You can avoid these dangers by cooking and melting water on a stove outside your cave. For this purpose, you can build a sheltered entrance pit, which will allow you to stay out of the worst of the weather while cooking, without being dangerous to you. You can even build seats and steps for your entrance pit.
To avoid using kerosene lamps, many snow cavers instead build a niche in the side of your snow cave, line it with aluminum, and place a single candle in it. This will give you sufficient light for the necessities without producing dangerous levels of carbon monoxide.
Another precaution is to take an ice ax handle or walking pole to punch vent holes into the roof at angles to the sides. Just be careful not to punch them through the thinnest part of the roof as that would compromise the stability of your snow cave. Refer back to #3.
6. Getting Trapped in the Snow Cave
Even if your snow cave is built as safely as possible, you will eventually want to and need to leave it. Therefore you want to avoid getting trapped inside it.
Aside from avalanches, the snowfall throughout the night can easily block the entrance to your cave and there is a good chance you will have to dig yourself out.
To make this easier, build your entrance facing down the slope. That way, the snow is easier to remove. This also makes building the snow cave in the first place easier as you can easily move the snow you dig out down the slope.
More importantly, keep your shovel and other crucial equipment inside the cave.
If you need to dig out, you will need your shovel, to be most effective. Any equipment left outside is also likely to get buried in the snow and it might not be possible to find.
If the snowfall is particularly heavy, you will want to consider regularly digging the entrance free throughout the night. This is to make sure you have an exit route should an emergency arise.
However, digging the entrance out during the night does carry the risk of overexerting yourself, as well as the dangers of sweating and then contracting hypothermia. At the same time, you have to make sure your vent holes are kept open at all times.
You will need to weigh the risks and consider if getting sufficient rest or easy escape will be more important for your survival, depending on the conditions and your plans for the subsequent days. As you can see so far, using snow caves can be tricky business for the uninitiated.
Physical injury in the wild, especially in a survival situation is often fatal, as it impedes your abilities to manage the situation. Therefore, care should be taken at all times to avoid any injury, even injury that in a normal, modern setting would be insignificant. Even mild sprains can cause you significant difficulties by slowing you down and limiting your capabilities.
Snow caves pose several particular risks for injury and particular care needs to be taken.
Injuries During the Build
In addition to the risks of hypothermia, injury can easily occur through the physical exertion of digging. In particular, make sure that you do not inadvertently injure your partner, especially as snow caves can be tight spaces.
It is recommended that you take turns digging. This will allow you to rest and avoid excessive sweat, though you should make sure to wear additional layers when resting. It will also avoid injury through the use of equipment like ice axes and shovels in close proximity to each other.
Injuries from Slipping
The other danger that snow caves pose is the risk of slips on icy surfaces. Care also needs to be taken to avoid slips, falls, and injuries through misuse of equipment.
The compacted snow used to create the structure can become quite slippery, especially if it warms up due to your body heat or the fire. This is a particular risk for the step leading from the sleeping area to the entrance. Make sure you remember where it is, and use a torch or other safe light source to find your way.
The sheltered entrance pit, if you build one, can also get really slippery. If you have cooked or melted water there, the heat can cause the snow to melt and then refreeze as ice. Avoid spilling water in this area if possible and take care in the morning to avoid slipping.
The snow cave itself might also become icy on the inside, although this is typically only a risk if you spend several nights in it. In a scenario where you are using your snow cave for several nights, make sure to spend some time on maintenance every day to make sure it remains safe.
Why Not Just Always Use a Tent?
The main reason to employ snow caves is that they provide much better insulation than tents and are therefore superior in very cold climates. While many mountaineers prefer to rely on four-season tents, snow caves are often the best option for the prepared survivalist.
Also keep in mind that tents include some of the same risks, namely avalanches. Even if you are using a tent, awareness of how to build a safe snow cave is a crucial skill in the event of an emergency or other survival situation.
Snow caves provide excellent shelter from the elements, especially in a wilderness situation. However, they are tricky constructions that pose a range of hazards. Fortunately, these hazards are easily avoidable for the experienced mountaineer or survivalists.
- The largest risks of carbon monoxide poisoning and cave-ins can be prevented through proper construction of the snow cave.
- The same applies to the risk of hypothermia from lack of adequate insulation but a properly built snow cave, in addition to suitable outdoor clothing can provide adequate protection.
- Other risks can be avoided by being aware of your surroundings in an attempt to avoid falling trees and avalanches, as well as avoiding the risk of injury.
- Proper maintenance of your snow cave means that it can be useful for more than one night.
How much warmer inside a snow cave is it versus outside? When temperatures outside are down to -40 degrees, inside a snow cave, the temperature can remain at a comparatively toasty 32 degrees (0° C)!
What is the difference between a snow cave and an igloo or quinzee? Snow caves are structures dug into a snowdrift to form a shelter and small living space. They are distinct from build-up structures like igloos and quinzees but do have similar insulating properties.
How do you sleep in the snow? To sleep in the snow, pack it down and make sure there is some type of insulation, preferably waterproof, between you and the ground.
Are igloos warm? Similarly to snow caves, igloos are warmed by human body heat. This allows the space to be heated to around freezing without any type of man-made heat source.
Main photo courtesy of Josh Lewis [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]