Learn how to build a winter shelter out of snow, space blankets, fallen branches, cave openings and more to survive a blizzard.
Shelters are particularly important in cold or rough weather or when you must remain in an area for a prolonged period of time. A good shelter should:
- Protect you from the wind and the elements.
- Be easily built to conserve energy.
Shelter Visibility
Remember that almost all outdoor shelters (especially snow shelters) have extremely poor contrast with the environment and will be difficult for search parties to see.
Keep a watch or make sure plenty of highly visible signals are left outside the shelter.
When to Set Up Camp
Better early than late. Always give yourself at least an hour before dark to set up your camp for the night, scour the local area for firewood and food, and get your fire started. You can estimate the amount of time until sunset with this technique:
- Face the sun and fully extend your arm towards the sun.
- Bend your wrist inwards so your fingers lie stacked one atop the other, parallel to the horizon.
- Position the sun atop your uppermost finger.
- Each finger between the sun and the horizon represents 15 minutes, so if you have four fingers between the horizon and the sun, you have approximately one hour before sunset.
Choosing Your Campsite
If you need immediate shelter don’t worry about this section, just build the quickest shelter you can with whatever you can find. If you have time to choose a site, look for the following:
- Area free from signs of avalanche, flash flooding, falling rocks, incoming tide, and lightning danger.
- Area free from animal kills and insect nests.
- Easy access to building and fuel materials.
- Absence of swampy ground, upright deadwood, and thick overhead vegetation near your campsite.
- Natural wind barriers.
- Area free of heavy snowdrift.
- Proximity to water. Avoid being either too far or too near a source of water. Mountain streams can rise 10 feet or more in a night, so note any high water marks or drift lines.
- Minor steepness of area and ground clear enough to build on (or which can be leveled and cleared with minimum effort).
- Thin timber for protection from snow and wind.
- View of the sky for seeing and signaling rescuers. Make sure they can see you as well.
- Area not located at the base of steep cliffs or rocky slopes in case of rockfall.
- Area not under leaning trees, even if they appear stable.
- Area not below high tide line along the shore or high water mark along a stream edge. Not located in a streambed or gully, even if dry.
- Area not located in coastal mud flats or isolated from the main shore by mudflats.
Helpful Tips for How to Build a Winter Shelter
Keeping Runoff Out of Your Shelter
This will be a problem anywhere you build a shelter that isn’t on snow or very high ground. Fortunately, it’s simple to solve. Just dig a small trench around the shelter to funnel rainwater away from the bottom of your shelter.
Tarp-Tying Tips
If you have a tarp or space blanket, using rocks in the corners to tie into knots will make a much more stable shelter than will just weighing down the corners.
Natural Shelters in All Seasons
Cave Shelters
Caves have the advantage of being ready-made shelters, but their disadvantages are significant. In particular:
- Your shelter does not help you get rescued because no one can see it.
- Rock walls absorb heat so will make staying warm much more difficult (and require more energy expenditure).
- Caves are usually already occupied by wildlife, some of it bigger than you.
- Caves tend to be damp and moldy, which makes staying warm and dry more difficult and increases the risk of infections for open wounds.
- Consider building a better shelter if you are staying put. As transient shelter, caves may be adequate.
- A lean-to of branches can be added to break the wind. Be cautious of caves or recesses surrounded by animal feces or tracks, and always be careful of snakes when first entering.
- Some caves are very deep and may have many twisting passages. Stay near the entrance or leave well-marked trails.
Rock Shelters
Rock shelters are really just windbreaks but may be helpful on open beaches or in some desert areas.
Build a rock shelter by stacking rocks into a U-shaped wall at least two feet high. Sleep against the inside of the wall. Build your fire in the mouth of the U.
90-Degree Shelter
The 90-Degree shelter can be built anywhere a 90-degree angle can be found. This includes bluffs above treeline, large boulders in the woods, and fallen trees.
- Locate an object with an approximate 90-degree angle between the ground and the back wall.
- If the ground is soft, create a shallow pit the size of your body at the corner of the angle.
- Line the pit with branches or bark slabs.
- Build a fire next to the pit so that you lie in the pit between the fire and the log. The maximal heat from such a fire is located at the corner of the 90-degree angle.
Leafy branches leaned over the pit will add additional protection. Wind breaks can be built at each edge of the angle to funnel wind away from you and the fire.
Mild Weather Shelters
In warm or mild weather it may not be worth the time or energy to build a real shelter. In this case a number of fast and excellent options exist. Carefully tended, very small fires will safely warm any of these shelters.
All of these will insulate better if roofed over with a space blanket (shiny side down) or plastic.
Short-Term Mild Weather Shelters
The easiest may be the low-hanging tree. Many large pines drape their branches almost to the ground, and under these lowermost branches you are relatively safe from wind and rain. They also tend to have a comfortable layer of needles already there.
Next is the space blanket shelter, made by hanging one cross-pole or rope from trees or rocks. Hang the space blanket over the cross-pole and tie each corner to the ground (or weight it with rocks). A quick, easy, and warm shelter. A tarp or your sheet of plastic (if not being used for water collection) will work in place of the space blanket.
A tube tent can be formed out of two garbage bags with the bottom of one bag split. The split bag is slid over the open end of the unsplit bag. The tent can be propped open with padded sticks or hung on a line run through the bags and tied to two trees. The tube tent can also be used without support just by crawling into it.
Leaning pine branches against a tree trunk, tree branch, or rope strung between two trees will also work. This is the classic lean-to. To ensure good shedding of rain, remember to build the ceiling at a 45º angle and pack the ceiling with at least three inches of leafy branches or, better yet, cover it with a plastic sheet.
Long-Term Mild Weather Shelters
If you are not traveling and need a longer term shelter, the above shelters will still work very well. Just insulate them more thoroughly and fortify them against the wind by lashing everything together with fish line or cord.
The Wickiup (for Individuals or Small Groups)
This is a quick, easy, and very good long-term shelter for one or two people. This is a tepee-shaped lean-to, which can be built on open ground around a tree or using fallen trees for support.
- Lean tree limbs, branches, or large leaves against each other to form a cone shape.
- Pile leaves, brush, dirt, bark, snow, or grass around the bottom and up the sides to the top, leaving an entrance at 90° to the prevailing wind.
- Lean more branches against this insulation to keep it in place.
- Break off or pull out any leaves or branches cluttering the inside. Your shelter is done.
The A-Frame (for Groups)
If you have a large number of people or want a more comfortable place to stay, try an A-frame:
- Construct your A-frame so that the prevailing wind strikes a back corner first.
- First place your roof cross-pole. This may be leaned against a tree or rock, hung between two of these, or supported by two poles planted into the ground.
- Tie sticks to each side of the cross pole so that they lean at a 60° angle to the ground.
- Next find wall materials. These may be bark, downward-pointing pine boughs, bundles of grass, or large tree or plant leaves.
- Start with the bottom row. Lay a single row of the material packed as tight as possible and tied to the angled sticks.
- Lay the rest of the rows, moving upwards. Wall material should be layered so that each bundle or section is overlapped by the bundle or section above it.
- Wall all but one end of the A-frame.
- Fill in gaps and leaks and put on a second layer if needed to prevent leaks. Put as much wall material on as you must to keep out the wind and rain and hold in heat. If you can see light through the wall it probably needs more insulation.
- Build your fire outside the open end of the A-frame, with a heat-reflecting rock or log on the other side of the fire if the weather is chilly.
A space blanket or more branches should be hung over the entrance on chilly nights unless the fire is going.
Surviving Your Snow Shelter
The presence of snow makes survival more difficult but finding shelter much easier. The makeshift snow saw can come in handy when constructing and repairing snow shelters.
When to Seek Shelter
It is important in cold weather, particularly in snow-covered areas, to seek shelter early on in a storm. Never try to find your way out while the storm is ongoing.
Construct a snow shelter and wait it out; otherwise you may wander in circles, stumble into dangerous shallows or icy slopes, or just burn up all your energy and freeze to death.
Vehicle vs. Shelter
It is warmer in a snow shelter than in vehicle wreckage, particularly in a strong wind, since the wreckage is out in the open and will NOT effectively seal in heat. Equally important, snow is a better insulator than the metal walls of a vehicle because of the insulating air spaces between snow crystals.
In addition, you want to conserve heat by minimizing the amount of space your body must heat up. In a car your body is trying to raise the temperature of the entire car.
Get out of your vehicle and dig a snow shelter right next to it. IF A WHITEOUT IS ONGOING, DON’T TAKE YOUR HAND OFF YOUR CAR! Do not, if your car still works, sit inside and run the engine for heat. Carbon monoxide, an invisible, odorless and TOXIC gas, may accumulate inside the car. You will get drowsy, fall asleep, and never wake up.
Tips When Utilizing Snow Shelters
Be aware of avalanche and lightning dangers when selecting your shelter site. Always take your gear in with you or it may be lost or buried outside. Store your food and water in the shelter with you, preferably next to your body, to keep it from freezing solid.
Mark your snow shelter well if you plan to use it more than once or even travel 200 yards from it. Snow shelters disappear into the landscape very quickly. For this same reason, large and prominent signals should be placed outside the shelter. Otherwise rescuers won’t be able to hear or see you.
Snow is a great insulator of sound as well as heat. Don’t count on hearing aircraft or rescuers through the walls of your snow shelter. Build large, prominent signals outside your shelter. In severe cold, dig deeper snow shelters with longer, more sloping entrances.
Problems in Snow Shelters
The five main problems in snow shelters are ventilation, drifting snow, melting snow, snow blindness, and the internal temperature gradient.
Snow Shelter Ventilation
To ensure adequate ventilation and avoid the buildup of carbon monoxide, leave at least one hole in the roof at a 90-degree angle to the prevailing wind. This need only be a few inches in width, wider if you have an open flame inside your shelter. A smaller hole should be poked through the opposite side of the shelter to allow cross ventilation.
Leave a branch in the shelter to occasionally clear the holes of snow. Leave the entrance open whenever a fire is going, and place the fire near the entrance hole. Watch each other for signs of carbon monoxide poisoning whenever an open flame is present at the entrance to your shelter.
Drifting Snow in Snow Shelter
Drifting snow will be a major problem if you fail to place your entrance at a 90° angle to the prevailing wind. It will blow straight in your front entrance or swirl in your back one. It is possible for drifting snow to block your entrance completely and force you to dig your way out.
Drifting snow will be a major problem even if you do position your entrance correctly because it can often block your ventilation hole, leaving you short on air or oversupplied with carbon monoxide. To avoid this, place your ventilation hole at the same angle to the wind as your door (90º). More importantly, keep a sturdy stick inside with you to clear it regularly during falling snow.
Melting Snow in Snow Shelter
Never sleep on the snow. Use anything to sleep on but the snow. It steals body heat and soaks your clothing. To prevent getting wet from melting snow, sleep on top of a couple of leafy branches or bundles of grass or sticks. Run your gloved hand or a smooth stick down the walls of your snow shelter to smooth them into a curve. You want melting roof snow to run down the sides, not to drip on you.
Don’t think a snow shelter is supposed to be as warm as home. It must be kept cold enough, inside and out, to support the frozen structure of the walls. Keep your fires small and don’t hesitate to open the ventilation holes more if the walls are becoming mushy.
Snow Blindness in Snow Shelter
You can get snow blindness even in a snow shelter. If you can see daylight through the walls, then you can get snow blindness. If it’s bright out, add snow to the outside of your snow shelter to cut down on the interior glow.
Temperature Gradient in Snow Shelter
The temperature gradient is caused by the tendency of hot air to rise above cold air. Temperature gradients in snow caves can go from 0 degrees Fahrenheit near the floor to 50 degrees near the ceiling.
Because you want as much of the heat as possible around your body, you should have your bed raised (in a side tunnel or on a raised snow platform) as high as possible, and your roof as low as possible.
Hang your snow-filled bottle near the roof to melt snow into water.
Precautions to Take While Digging Your Shelter
Take off your outer layer of clothes. Don’t stay so bundled up that you sweat.
Use some sort of digging tool, be it a piece of metal, a square of bark, or a stick. Avoid frostbite by avoiding the use of your hands alone unless thickly gloved.
Fine-Tuning Your Snow Shelter
If the roof of your snow shelter melts and drips excessively, the roof is too thick. Scrape some off or add more ventilation.
If the roof of your snow shelter is frosted or icy in the morning, it is probably too thin. Add some more snow on top.
If the roof of the snow shelter settles as much as five inches, nothing is wrong. Just add more snow on top of the shelter and let it settle and freeze. After the new layer freezes, scrape away snow from the inside.
Maximizing Warmth in a Snow Shelter
The most important way to maximize warmth is to avoid sleeping directly on the snow.
- Sleep on evergreen branches (the softer the better), extra clothes, plastic, or a backpack. Use bark, dirt, branches, and leaves, even rocks if it means keeping dry.
- Also, if there is more than one of you, sleep close together to minimize heat loss and share body heat.
- Keep your roof low and your bed high.
- Keep your entrance small and blocked when not in use. Dig your entrance lower than the floor of your shelter.
- Remember that snow closer to the ground is warmer than fresh-fallen snow or surface snow.
- Sleep whenever you can. Going to sleep will not kill you if you are not severely hypothermic. You will awaken if you get too cold, and sleeping saves energy. You help no one by avoiding sleep.
This excerpt has been reprinted with permission from The Extreme Survival Almanac, published by Paladin Press, 2002. The Extreme Survival Almanac: Everything You Need to Know to Live Through a Shipwreck, Plane Crash, or Any Outdoor Crisis Imaginable.
