I'm a snowmobiler and have a good kit on board all the time. I am generally well prepared, but lack info on building a snow cave, dimensions for a 1 man, 2man, or 3man. How and where to put the cold well, how much ventilation and where? Do I burn a candle, and if so more ventilation? What kind of temps would be considered normal inside a snow cave relative to outside?

And any info gained from experience would be a great help as well. Thanks in advance for all of your input. Love this sight!

It might be kinda hard to find, but Ray Mears did a good piece on it in his extreme survival episode on The Alps. You might be able to find it on youtube. Unless you have a way to play his DVDs...

Finding a pre-packed mound of snow is preferable to having to build one yourself. A 5-ft deep drift of settled snow against a downed mass of tree roots or something would be ideal, and would save a lot of energy at a time when you need to conserve what you've got. If you can't find a large enough mound, you'll either have to add to a small one, or make one from scratch. Then, you'll either have to pack it down, or give it some time to set, or all it is is a mound of loose snow that will collapse when you start digging into it.

Since everyone in the cave will be huddled together to conserve warmth, the size probably won't vary all that much. Besides, the size will be limited by the size of the snow mound. A sleeping area the size of a twin bed is fine for two people, a double bed for three, etc.

Once you have your mound, the first thing you need to do is mark the wall thickness, which should be about a foot or so. Find some thin branches, break them all to about a foot in length, and push then in to their length all over the snow mound.

If there are two or more people involved, make sure at least one is always outside the cave while you're digging. Snow caves have been known to collapse while under construction, although once finished, it doesn't happen very often.

Your cave opening should be on the downwind side of the mound. If you can, try to dig slightly upward, making a ramp-type opening just slightly larger than the crawling size of the largest person. If you can make the opening of the snow cave lower than the platform, you can probably eliminate taking the time to make a separate cold well. Since heat rises, you will want the sleeping platform to be the highest point inside, to trap whatever heat you can provide.

When you start carving upward, stop when you hit the tips of the branches you inserted from the outside. Try to carve the ceiling in an arc, so melting snow/ice will run down the walls instead of dripping onto you and the platform.

If you can pile fir or pine branches on top of the raised platform, it would help to insulate you from direct contact with the ice.

The 2" ventilation hole should be near the top of the mound. It doesn't need to be larger. Think of air as water, and you'll see how much air can pour in through a continously-open 2" hole, just like water can.

Find a long, slim stick and leave it in the hole, with the base on or near the platform. Move the stick to keep the hole open.

Block the opening of the entrance with a pack or other moveable object. Keep any digging equipment inside the cave, near you; if it snows a lot during the night, you may have to dig your way out.

Lighting a candle or tea light will increase the temperature in the cave, but will also use up oxygen, so make sure the vent hole is always open (the original 2" is fine). Keep in mind that although a candle will raise the temperature inside and improve moral, the temps in the cave will not rise much above freezing, so don't expect it.

Fires are not usually burned in snow caves, as the heat they give off is excessive, and will tend to melt the cave.

If you have children with you, please take the time to explain the WHY of everything you're doing, especially the vent hole. Not only will talking to them calm them, but they will be absorbing valuable knowledge. And if you fall asleep, they can help keep the hole open.

Also if you have children with you, tell them NOT to leave the cave just to pee. They will certainly get chilled, and possbily get lost, esp at night. You might want to dig a hole in a "corner" just for that purpose right in the beginning.

Sue

Wow, not much I can add to that! Only thing that comes to mind is that digging a snowcave is hard work, and if you are not careful you will start to sweat, a bad thing in extreme cold. So start removing layers as you warm up, and if you get close to breaking a sweat, stop for a while, or let your buddies dig...

Exactly, they are HARD work and take a LOT longer than you think to make. So if you need to hike out of where you are at maybe a less 'hard to build' shelter would be a good idea.

Another shelter I suggest is using the base of a tree and putting branches around the top to shelter yourself under them... this is normally almost already always dug-out to some degree (branches and leaves prevent snow from filling around the base), and you don't have to dig much if you do.

Also check out for fallen trees to just dig out under them instead of an entire cave.

I've solo built 4 snow caves and 1 igloo in my life and helped on at least twice that number. It was never a life or death situation, we used to go camping once a year in the mountains just to get used to making snow caves. They are a good bit warmer than outside or in a tent, air temp does get above freezing, snow acts as an insulator. Make sure you smooth the roof or it will be dripping on you ALL night long (learned how well you need to smooth it off of the first cave.) Most of the snowcaves I made were much bigger than they should have been, makes them too cold, but easier to move in. Our cold well was always integrated with the enterance, dig down over then back up to provide the well at the enterance, then you climb up onto the sleeping platform. It keeps the wind from moving as much air in and out, but makes for slightly more digging. If you can sit up in the cave it's too big. We never provided an air hole, the old timer mountaineer who taught us said the snow would breathe enough. My scout troop like i said went every year and we had enough boys that 10-12 snowcaves for multiple people were made each year. That's how we made all of them. I frequently used a candle in ours, but always made a shelf/cutout for it and set it there. The hole above it by morning would go most of the way to the surface.

Some additional thoughts, everyone always got wet digging snow caves. Not always sweaty, but you are crawling around in the snow. Standard practice for us was to bring a dry set of clothes and change when we got the snow cave built so we were dry. YMMV. The last thing, if you are going to plan on using a snow cave as your emergency shelter practice practice practice. My first cave fell in while I was digging it. I helped lots of others whose caves fell in while digging. Also helped one guy who was a bit clausterphobic when he busted out of his at 2:30 am.

Finally, igloos take too long to make to use an emergency shelter

Not a thing I can add to that other than insulate yourself from the floor of the cave as best you can. Bring the thickest sleeping pad you own.

Personally, I find that the lack of good packed piles makes it harder to make a proper snow cave than it is sometimes worth in terms of time spent looking. I usually make a snow trench- exactly what it sounds like. Insulate the bottom, put supports across the top, then more insulation, and pile snow on top. Not as warm, but if you can't find a proper snow mound it is a lot better than nothing.

You can find hollows as was mentioned under trees with low branches, I like spruces myself for this because they go so low to the ground. But you need to be super careful if you have any kind of flame- remember, it's an evergreen full of pitch!! That has the potential to turn into a great signal fire, one that runs and screams and flails about. :P

In any case, signal markers are critical! Orange, red, blue, any neon colors, these show up pretty well. A pile of snow looks like, well, snow from any significant distance.

I've made more igloos that snow caves, less claustrophobic for me. One bit of advice - you do get very wet, including your hands, a pair of sturdy rubber gloves under your work mitts will keep your hands drier and warmer. Home Depot stocks nice, lined gloves intended to wear while laying / grouting tile.

In my area this is excellent advice. Also, if one is in a true emergency situation it pays to keep in mind that it takes much less time and energy to create a snow trench or a shelter under a good-sized evergreen than it does to excavate a snow cave. The latter, offering as it does the possibility of a fire (warning noted, ironraven!), would actually be my first choice.

Frank2135

I don't recommend snow caves at all. I won't risk my life inside one of those deathtraps overnight. I had one collapse on top of a me and a friend. We were completely trapped in the snow. The weight pinned us down completely, we never would have been able to dig our way out. The only thing that saved us was that we had 8 friends outside the snow cave who dug us out. If they hadn't seen the cave collapse, we would have been stuck. I was shouting at the top of my voice and they couldn't hear anything outside.

It turned out alright, but if we had been sleeping in the cave overnight when it collapsed, I wouldn't be here. Collapses are probably few and far between, but it only takes one collapse to trap you completely. The only situation I could see someone risking their lives in one of those is in an emergency shelter, life or death situation, where the risk is worth it. In that case, I can't see the justification of expelling all that energy, when there are easier, safer snow shelters which can be built.