Unless you’re in a fairly large group (three or more) close to civilization or the parking lot, it’s a good idea to be prepared to survive a night out. If you’ve got enough clothing and a shovel, it’s possible to dig a snow cave and sit out the dark hours, but doing so is problematic because your clothing gets wet while you’re digging the cave. Nonetheless, a couple recently survived an unplanned night on Mount Rainier by using a snow cave. Outside of Aspen, another couple survived a stormy night out just yards from a hut. Due to a storm they couldn’t find the cozy shelter, and did an open bivvy in their sleeping bags which from news reports sounded marginal. And sadly, up on Mount Hood a group of three did not survive, and it’s assumed at least one person in the group ended up in an emergency bivouac somewhere on the mountain — a bivouac that obviously did not work out.
My theory has always been that having a good shovel and decent clothing could get me through nearly anything. But I do throw in a bivvy sack now and then, when I’m in a small group and our plan takes us deep into the backcountry away from an easy egress.
A snowcave may be the best of survival shelters. Some WildSnow.com tips for digging one when you’ve got minimal gear, and surviving after you dig:
1. Find a wind swale, cornice face or treewell face where you can start digging horizontally. This saves you from burrowing like a mole and doing the extra digging required if you need to go down then sideways. Also, branching a cave from a pit means you run the risk of the pit filling back up from wind drift, and trapping you in the cave or at least making exit difficult.
2. If you find a good semi-vertical face to start digging, test and see if you can cut uniform blocks with your shovel. If so, start with a fairly large opening, and enlarge into your sleeping chamber as soon as practical. When all is ready, wall the opening back up with the blocks, leaving a small door opening.
3. In either case, be sure to make your sleeping chamber higher than the door, so it’ll trap warm air from your body and breath.
4. Before starting work, strip off ALL non-essential clothing and store so it stays dry — especially any down gear. If you have hardshell layers, wear them over nearly nothing while you’re working. Once you’re digging inside the entrance tunnel and beyond, you’ll be amazed how warm you’ll get.
5. Once in the cave for the night, place dry clothing next to skin and damp clothing on the outside. Sit on your backpack. Keep your boots on but loosen as much as possible. If you feel your feet getting cold, take the liners out of the boots and store under your clothing, then place your feet under your partner’s torso clothing. DO NOT leave your liners in your boots, as you many be borderline hypothermic in the morning, and placing your cold feet in frozen boots could cause severe frostbite.
6. If you have a stove, you’ll definitely need a ceiling vent in your cave. Be super careful about this as carbon monoxide poisoning will at best impair your judgment. If you don’t have a stove and your cave is large with an open doorway you probably don’t need a vent, but consider a small one anyhow to keep the air a bit drier and fresher. You can always plug it with a spare piece of clothing or snowball.
7. Use good judgment if you’re lost or can’t return to civilization, and don’t push into the night, but rather set up your survival camp when you’ve still got energy and perhaps daylight.
8. Always always carry a bit of extra high-calorie fat/protein food. Sitting out a night in a snowcave with a bit of cheese or jerky to keep you company can be uncomfortable but totally safe. Doing so if you haven’t eaten for hours could still result in a hypothermia situation from which you might not return.
9. If you’re warm and have food, eating snow to stay hydrated works fine. But never never eat snow if you’re even close to being chilled.
Beyond the snowcave, if you’re short on time you can simply dig a trench, lay your skis over it, and cover the skis with snow blocks. To do this right, keep the trench as small as possible so you can plug the end with a backpack or snow blocks once you’re inside. If you totally wall yourself in, it’ll be as warm as a snowcave, but so small it will be difficult to move to stay warm. In my experience, the trench works better if you have a ground cover and sleeping bags, while the snowcave works better if you’re short on gear. Though again, the main problem with snowcave building is getting wet. If you’re short on clothing, be very wary of this. Getting wet can kill you.
I should also mention that if your skiing is done below or at timberline most of the time, one of the best ways to survive a night is to simply build a large fire and hang out next to it. To do so, you need to be carrying a functional fire starting kit and know what you’re doing. Practice helps (as it does in the case of snow caves). A while back we had a good post and comment thread about winter fire starting.
Lastly, in all three examples mentioned above the protagonists had no way of communicating with civilization, and thus triggered or came close to triggering large rescue efforts. I find this amazing and tragic, as so many communication options now exist. Seriously folks, at least carry a Spot Messenger, and if you’re hut tripping and carrying a sleeping bag, throw in a bivvy sack so you can spend a night out without your sleeping bag getting soaked.
I recommend the SOL Escape Bivvy, mainly because it’s waterproof/breathable. It is of paramount importance that your bivvy be of breathable fabric. Not only will a non-breathable bivvy immerse you in cold moist air, but you’re more likely to suffocate if you fall asleep and lose your ventilation.