Building Snow Caves
By David Loveland

It's winter. Fall finally gave way to nature's eternal cycle. Now it gets dark at 6:00 PM, its cold outside, and you're bored and restless. TV and Nintendo don't take the place of those great morning hikes or after-work mountain biking. Don't mope about it--get out make the most out of the winter season. GearReview.com is going to help you by introducing you to snow caves. Rather than hauling that four-season tent up the mountain on your back, just bring a shovel, add a little time, and poof! (Nearly) instant shelter.

As more people head into winter backcountry, more of them find themselves needing shelter. This winter you'll hear reports of snowmobilers whose machines break down far from help leaving them stranded, without proper equipment, forced to remain outside overnight. I've seen two such cases in the past week in Utah's backcountry. (I'll suppress my inclination to jump on a soapbox and point out the need for anyone who heads in to the backcountry in winter to have proper equipment, like snowshoes and a shovel.)

Snowboarders often hike several miles through avalanche prone slopes to catch pristine snow, untouched since the last powder dump. They too can find themselves spending an unexpected night on the mountain.

Snow caves aren't only for stranded motorists and lost backwoods hikers, but also for winter backcountry campers. Building a snow cave under favorable circumstances helps prepare you for a time when a snow cave may be a lifesaver, not just a planned replacement for a tent. The self-confidence that comes from knowing what to do in an emergency is worth the time investment.

How important is shelter? In winter, it's more important than food and water. The human body can exist three minutes without air, three days without water, three weeks without food, but only about three hours without shelter in sub-freezing temperatures. A snow cave can be built rather quickly, and keeps humans surprisingly warm. Convinced? Ok, enough justification, let's build a snow cave.

The Recipe

First comes location. Of course, you'll need lots of the main ingredient: snow. If you're building your first snow cave, you might want to start in the backyard, if there is enough snow. A foot or so will do, if you don't mind shoveling a bit. Another good place to practice is up any nearby mountain canyon. They all get their share of the white stuff, and being close to home, you can afford to make mistakes. In a survival situation, look for an easy place to dig, such as a drifted snow bank. All you have to do is dig a tunnel, hollow out a room, and sleep out the danger.

Let's assume you're not in your backyard, but up in the mountains. Make sure you are outside of any avalanche path. Just because there are trees around does not guarantee you won't be buried under an avalanche. Check up slope for steep ridges, especially corniced ridge tops or wind-loaded slopes. Also, watch for trees bent or broken above the ground, which indicate prior avalanches.

Look for an open space surrounded by tall pines, ideally about 10 feet in radius. This collects not only snow falling straight down, but also snow falling from tree branches. Make a snow pile about four feet high and five feet in diameter, then get on top and tramp it down. This is an important step; forget it and you may experience a disappointing cave-in when you're scraping the interior ceiling. Snowshoes help tramp down the snow at first, but after a few minutes take them off and jump up and down with just boots on. The snowshoes disperse your weight too much for good compaction.

Make the hole near the bottom of the snow pile. (I'll explain why later.) Since the hole gets wider as you dig, make it a shovel's width to start. As you dig out the entrance tunnel, pile the removed snow on top of the cave, adding to the height and width as you go. Think of this as turning the snow pile inside out.

Digging while on the ground and crawling inside the cave gets you very wet. The exertion keeps you warm, but after you stop you'll get cold, so it is essential to have dry clothing to wear when you finish. Even Gore-TexÆ can't keep you dry if you get snow up under it! In an emergency, work slowly, if conditions permit, to prevent dampening your clothes with sweat. You may want to remove some layers while you work so you'll have dry clothes to sleep in.

Once you hollow out the cave enough to fit inside, get up on top and tramp it down again. You need to have about three feet of snow on top or you'll fall through. You should have enough if you piled snow from the interior on top. After this final tramping, finish hollowing out the cave. A great scraping shovel is the Ortovox Professional (which you should be carrying anyway for avalanche safety) or an army-style folding shovel. With either you can turn the blade 90 degrees to the handle, which makes quick work of scraping the cave's sides and top. While working inside, you'll also need some kind of light. A small candle works well, as does a headlamp. If you use a candle, protect it from falling snow, since you'll be throwing a lot of it around.

As you scrape snow off the sides and top, and push it towards the entrance, it is very helpful to have someone on the outside pulling it out. Otherwise, you have to maneuver yourself inside the cave, alternating between scraping and pushing the snow out of the entrance with your feet. Sometimes a blocked entrance can be unnerving--you may feel like you just plugged your only escape. Just move down the tunnel and push the snow the out. For the claustrophobic, remember you're only a few feet under the snow. In an emergency (a panic attack?) some serious pushing will bust through the top, but ruin the snow cave.

How big should the cave be? In an emergency, you won't have a sleeping bag and pad, so you'll sleep curled in a ball and don't need a gigantic shelter. The smaller the cave the better. You need just enough space to lay down in the fetal position. Tear off some pine boughs and put them inside to sleep on. Place additional boughs over you. It should only take about 30 minutes to build a small cave.

For camping, you should spend more time enlarging the cave and adding niceties. For example, a sleeping shelf, above the entrance, keeps you warmer. The shelf allows cold air to fall down and away from you, as you sleep in the warmer air that naturally rises to the top. This is why you want to make the entrance as low as possible. Also consider a cooking shelf for you stove and candles.

Any snow cave needs at least two vent holes. I recommend one vent at the top of the cave, and another at mid-height on the wall opposite the entrance. Poke an avalanche probe or dead branch through the walls for vents. I usually block the entrance with snow just before I go to sleep, and make it a vent hole, too. One push of your boot opens the entrance. Periodically check the vents to ensure they aren't blocked by drifting snow.

Make the walls as smooth as possible. Your body heat, not to mention a candle or two, will cause melting. Water from the walls and roof will find any uneven surface and drip on you. With smooth walls and a nice curved ceiling the melt water runs down the sides to refreeze at the bottom. Also keep the walls back, away from your sleeping bag to stay dry, or dig small trenches along the wall to let the melting water drain away from you. Don't let the vapor in the air overly concern you, especially when you're working inside, hollowing it out. This is normal--just part of being warm and comfortable.

Before retiring to your cave, mark the site with poles or flags to alert any passers-by and keep them from walking over, or worse, falling into your cave. Crawl in, put on your dry clothing and enjoy a 100% natural shelter, as warm or warmer than a tent.

David Loveland is a new contributor to GearReview.com.