Question:
Actually snow is rather porous and if you build a good cave you can usually get by without the hole for normal occupancy. The major cause of death in avalanches is suffocation. Snow is dangerously hermetic!
Yes, suffocation is the major cause of avalanche death. However this is a *very* different situation. The typical avalanche victim has snow packed tightly all around his face with little surface area in the snow to exchange air. Often in fact the mouth and nose will be snow-packed. A good snow cave, on the other hand, provides probably 300-500 square feet of snow surface for air exchange. My experience convinces me that this is adequate. I have slept several times in snow caves waking up to find not only the upper air hole but also the door covered with fresh snow. I was still alive last I checked and not even brain damaged by it (I was this way to start with 
). Consider the experience of the victims of the infamous Oregon Episcopal School accident on Mt. Hood several years ago. I think there were about 8 people in a small snow cave – enough that some others had to stay outside for lack of room. Nobody died of suffocation, the deaths were due to hypothermia (although this may have been aided by hypoxia). The survivors show no signs of brain damage or other long term effects of hypoxia. This was a much worse situation air-wise than a good snow cave. A candle should be buned inside a cave to indicate air quality. (BTW, how effective is it at indicating dangerous levels of CO2?)
If it makes you feel better go ahead. Are you going to stay awake all night to watch the candle? If not it will just consume oxygen. Although it is possible to use a stove inside a cave, it is preferable to cook outside to avoid excess CO2 (eg. in an open trench in front of the entrance tunnel).
Depends on the weather. I’ve never had any problem cooking in a snow cave except that boiling water makes for a nice dense fog inside. If the weather is nasty I prefer to cook inside where I can take off my mittens or heavy gloves. CO is not a problem with ethanol stoves (why do people use petrol stoves anyway?)
Cause they burn hotter than ethanol stoves. Probably a liter of petrol (gasoline) has more heating value than an equivalent weight of ethanol also. You pays your money and you takes your choice. However I doubt that ethanol is really any better than petrol for CO. Either will probably produce CO if burned with insufficient oxygen.
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– Hide quoted text — Show quoted text – Actually snow is rather porous and if you build a good cave you can usually get by without the hole for normal occupancy. The major cause of death in avalanches is suffocation. Snow is dangerously hermetic! Yes, suffocation is the major cause of avalanche death. However this is a *very* different situation. The typical avalanche victim has snow packed tightly all around his face with little surface area in the snow to exchange air. Often in fact the mouth and nose will be snow-packed. A good snow cave, on the other hand, provides probably 300-500 square feet of snow surface for air exchange. My experience convinces me that this is adequate. I have slept several times in snow caves waking up to find not only the upper air hole but also the door covered with fresh snow. I was still alive last I checked and not even brain damaged by it (I was this way to start with ).
An interesting exercise - if you are at a ski area this winter, and they release avalanches (with mortar shells or whatever) for safety, and those areas are in-bounds and reachable – ski up to the edge and examine the snow. It’s dense. It’s not like the fluffy stuff that falls out of the sky. It’s more like cement. A real eye-opener. (Jackson Hole is a good place to do this.) So – I doubt if that compacted snow is anywhere near as porus as the more pristine stuff – yet another big difference between a snow cave and an avalanche.
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I have before been out winter camping but always sleept overnight in a tent, and the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end. Henrik Carlsen
Two good books have information on snow shelters: The Backpacker’s Handbook by Chris Townsend and Harsh Weather Camping by Sam Curtis. In the Backpacker’s Handbook – the description for Snow Caves: In deep snow you can dig a shelter as snow is a good insulator and cuts wind. You need several hours at least to dig. Because digging snow is hot work, strip off warmwear so it doesn’t become soaked with sweat. Start by digging a narrow, horizontal trench into a bank of snow at least 6 feet deep. Once you are into the snow back you can dig out the area around it to form a waist-level sleeping platforms. These are raised so that cold air will sink into the trench. Roof should be curved and smooth. How big the cave is depends on how many it must shelter, how much time you have and how much snow there is. The entrance should slope upward out of the cave and be kept small to prevent snow and wind blowing in. Make sure to include an air inlet to prevent carbon monoxide buildup when cooking. Becareful where you put things, especialy small items in a snow shelter, (and when digging it) – even more so than when camping on snow, as things get lost easily. (There are pictures of what it will look like, during construction and afterwards.) In the Harsh Weather Camping: To start with using lightweight shovels; aluminum-bladed shovels with detachable wooden handles. Wear waterproof outer garments and start your work well before dark. Again, good snow cave requires compacted snow about six feet dep. Drifts on the lee side of ridges offer ideal conditions. However, take extreme caution in steep mountainous areas where excellen snow cave conditions may coincide with excellent avalance conditions. Start by digging a 3′ x 3′ tunnel, into the face of the snow drift. Ceiling should be arched to provide structural support and should extend into the snow for 3 to 4 feet. One person works on the tunnel, another person can push the excavated snow downslope to form a flat entrance platform. You can have a one domehsaped room 7′x7′ room high enough to sit up in (house 4 people and gear), or one to three sleeping alcoves 4′ wide 4′ high and 7′ long. These alcoves, which radiate off the entrance tunnel will each sleep two people and have a community cooking area where the alcoves meet the entrance. Dig living area slightly higher than the entrance tunnel to keep cold air out. Arch ceiling to form a good structural support and smooth off rough edges that would form natural drip spots once the cave is warmed by body heat and cook stove heat. As you dig out the cave, one person should remain near the entrance to throw loose snow outside and watch for problems. After cave is dug, one with the basket of your ski pole poke a vent hole through the ceiling to the outside, to allow proper ventilation. Second, using solid chunks of snow remaining from your digging construct a windbreak around the entrance to prevent snow drifts from closingit. Keep shovels inside. In Backpacker Magazine (October 1993) some cold weather tips:When and if you take your gloves off, put them inside your coat next to your body. When clothes get wet, change into dry set, then sleep with the wet stuff to dry it out. Contrary to popular myth, snowcaves are only appropriate when you intend to spend more than two nights in one place, because they are too much work and you usually get too sweaty to warrant building a new one every night. Good Luck, Roma Isaacs Tallahassee, FL
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Moisture is a big question in my mind. Can your warm bodies raise the temp enough to get the ceiling dripping? Hints: Keep the walls Smooth and rounded such that if you have condensation that doesn’t freeze to the wall/ceiling (likely on a mild night), the liquid will flow along the rounded wall and not drip onto your nose.
After constructing the snow cave, I bring an open pan of water to a rolling boil inside the cave. The steam effectively ices over the inside of the cave. That way, you don’t get snowed on when you move around inside the cave. — Richard | Department of Pharmacology <<KM6ED | | University of California at San Diego Tel (619) 534-2298 | | La Jolla, CA 92093-0636 FAX (619) 534-7461 |
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What if it’s snowing? What does one do about snow clogging up the breathing hole(s)? Actually snow is rather porous and if you build a good cave you can usually get by without the hole for normal occupancy.
The major cause of death in avalanches is suffocation. Snow is dangerously hermetic! More than 30cm of snow (typical wall thickness in snow caves) is hermetic for practical purposes. Ventilation through the entrance tunnel, whose opening to the outside should be at a lower level than the floor of the cave (thermal isolation), may be insufficient. Therefore a ventilation opening, typically a hole made with a ski pole, is a must. The ski pole can be left in place to be used for cleaning the ventilation hole. A ventilation hole should also be made to ‘pile’ type snow huts, as a door made of snow bricks is usually used. A candle should be buned inside a cave to indicate air quality. (BTW, how effective is it at indicating dangerous levels of CO2?) However I would keep it open while cooking to vent the combustion products, particularly any carbon monoxide.
Although it is possible to use a stove inside a cave, it is preferable to cook outside to avoid excess CO2 (eg. in an open trench in front of the entrance tunnel). CO is not a problem with ethanol stoves (why do people use petrol stoves anyway?) Markus Bjoerksten
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| It also helps to dress waterproof in appropriate places when you do it. | Some folks wear a rain suit. | | I have mixed opinions on this. I have never used a rain suit to build a | serious cave (and I have built serious caves). I suggest doing both.
I have built igloos, snow caves, and mound houses — and slept very comfortably in same. Conditions from drippy to -20F & very windy. I don’t personally use a rain suit — but waterproof gloves/mittens can help a lot at times. Hands can get wet handling snow blocks. Some folks, however, do prefer waterproof outerwear. Although I don’t agree with them personally, it does illustrate that unless it is very cold out you can get wet in this activity. As to time to build — depends on how good you are and what conditions are like. Vilhalmur Steffanson (spelling?), a noted Arctic explorer said he routinely built an igloo. His rule of thumb was to start looking for suitable snow about two hours before dark. He felt that during the next hour’s travelling he’d find suitable snow, and about an hour for two men to build a good igloo. –Bob
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| The structure is remarkably strong, so strong in fact that we | could actually climb up the side and stand on top. The igloo | was large enough to accomodate five or six people inside and | myself and two friends spent the night in the structure. Steffanson claimed that a well made igloo (set, glazed inside) will support a polar bear. I don’t know whether that was anecdotal or personal experience of his….
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recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince
I have built a snow cave once and seen several. For a snow cave you need plenty of hard snow in vertical formation, like in a snow drift or bank. The open fjells of northern Lapland are often good for snow caves. To check out the depth of the snow bank, experienced diggers have a 3 m long metal pole, made of sections that can be screwed together. Do not use tent poles, most likely you can’t get them out of the snow. Digging a cave takes time, at first time plan a day for it. Even with experience most people do not want to dig a cave for just a single night. For tools you need one or more shovels and a snow saw or snow knife. The shovel should be very strong, we had two small aluminum shovels, a entrenching tool for the really hard parts and a grain shovel for moving the loose pieces of snow. For a saw we used a large-toothed ordinary saw. The digging is usually wet, there is snow flying around and often you sit in the snow, too. Do not start the cave at the bottom of the snow bank, since you are going to extract a large amount of snow that has to go somewhere. First dig a short tunnel inwards, either level or rising. Make it as small as possible. The go upwards and when you have enough height dig level again, so you get a sleeping platform. The platform should be well above the top of the door. Ventilation is very important in a snow cave, it is advisable to bring a candle in as early as possible in the operation. If the candle stops burning, that means that you do not have enough air and better get out. To ventilate the cave punch a couple of holes through the front wall with ski poles and make them so large that the basket at the end of the pole goes through, too. It might be a good idea to chip some snow off from outside under the hole, so that the ventilation holes do not clog. With our cave we had too much ventilation so that it never got very warm there. But of course it is always better to err on the safe side. For cooking dig a shelve in to the wall and dig a hood above the stove with a hole to outside. Making food in a cave is nice, since there is no snowfall and you can sit in your sleeping bag, being warm and comfy. The ceiling of the cave should be dome shaped and designed so that the condensation will flow to the sides, instead of dripping on people. Try to design a surface with no local maxims or minims. Half of the fun in snow camping is that you can build anything. Like a kitchen, a garden set with chairs and tables or even a nice snow-C with a view, for which we often bring a styrofoam toilet seat. Instead of a snow cave or an igloo you can get almost as warm by digging your tent in the snow and building a wall outside it. With several tents you get a nice fortified village . The best we have had is six tents and three caves in one place. A really pretty little base camp. — Helsinki University of Technology, Computer Center, Finland
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| The structure is remarkably strong, so strong in fact that we | could actually climb up the side and stand on top. The igloo | was large enough to accomodate five or six people inside and | myself and two friends spent the night in the structure. | | Moisture is a big question in my mind. Can your warm bodies raise | the temp enough to get the ceiling dripping? | | Does the moisture from your breath recondense on the ceiling? | | Would you need something over your sleeping bag to stay dry? | I don’t recall moisture being a big problem. It seems that the walls absorbed moisture in much the same way a snowball will absorb water. The bottom line though is the sleeping bags stayed dry without covering. | I would guess additional snow is no problem, and lightly falling | rain shouldn’t be either as if the temp is low, it will give | your igloo a crunchy shell. But isn’t there a big danger of | a good amount of rain making your cozy home into a slushy mess | that will collapse on you? Rain would definitely pose a problem, and in fact, rain is what resulted in the igloo’s final collapse. The rain thinned to walls until the ceiling of the dome collapsed. – Bill Miller
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What if it’s snowing? What does one do about snow clogging up the breathing hole(s)?
Actually snow is rather porous and if you build a good cave you can usually get by without the hole for normal occupancy. However I would keep it open while cooking to vent the combustion products, particularly any carbon monoxide.
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Moisture is a big question in my mind. Can your warm bodies raise the temp enough to get the ceiling dripping? Does the moisture from your breath recondense on the ceiling? Would you need something over your sleeping bag to stay dry?
Hints: Keep the walls Smooth and rounded such that if you have condensation that doesn’t freeze to the wall/ceiling (likely on a mild night), the liquid will flow along the rounded wall and not drip onto your nose. Another helper, in any of these snow/ice residences, is to have the entrance lower than your sleeping space… you know, the heat rises kind of thing. If you are digging into a snow drift, dig up. Wendy
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I have before been out winter camping but always sleept overnight in a tent, and the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end. Henrik Carlsen
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I have before been out winter camping but always sleept overnight in a tent, and the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end. Henrik Carlsen
I saw an article in this month’s issue of Backpacking. I’ll bring it in tomorrow and type out what it says. It seemed to be the ultimate how to on snow camping. Roma Isaacs Tallahassee, FL
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I have before been out winter camping but always sleept overnight in a tent, the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end.
1) Far fewer people who use the net use it in winter. Many migrate (maybe like caribbo herds) from rec.b to rec.skiing 2) Snow based shelters are fairly well documented in the written literature and their printing/diagramming ability exceeds that of the net. Get a book on winter mountaineering. 3) It’s mostly elbow grease and the West has had a good drought for the past seven years so it’s been hard to do out here. This takes time. 4) The one piece of info you can get from the net is that most shovels are inadequate flimsy things, and you want a good strong shovel. 5) Making igloos, it helps to have a snow saw. But it is not essential. 6) There is not rule number 6. 7) As the commerical says, Just do it. [This will teach the effort, the length of time it takes, etc.] Resident Cynic, Rock of Ages Home for Retired Hackers {uunet,mailrus,other gateways}!ames!eugene Second Favorite email message: 550 Host unknown (Authoritative answer from name server): Address family not supported by protocol family A Ref: Mathematics and Plausible Reasoning, vol. 1, G. Polya
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I have before been out winter camping but always sleept overnight in a tent, and the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end. Henrik Carlsen
I believe there is a detailed discription in "The Backpackers Handbook" by Townsend. Jeff Pearson Lockheed Sunnyvale Standard Disclaimer "aint gravity a bitch"
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… | 7) As the commerical says, Just do it. | [This will teach the effort, the length of time it takes, etc.] It also helps to dress waterproof in appropriate places when you do it. Some folks wear a rain suit.
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Watching "Trailside" on PBS one day, they built a snow cave but did not go into too much detail. From what I understood, it basically starts with a pile of snow, periodically packed down as it is being built up. Once a large enough pile is made, you start tunnelling into it and hollow out the inside. Sounded simple enough. Two things that I do remeber about it though was to ensure that you poke a couple of vent holes in the top, and that the guy had the entrance below the level of the surrounding snow (ie dug a trough in the snow then into the cave). Apparently this helps keep the heat from escaping by having the entrance as low as possible. Cheers…Stuart
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I have before been out winter camping but always sleept overnight in a tent, and the season comes closer. So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some experince in doing so. Is the principle the same as building an iglo as the eskimos. Any good ideas on how to start and where to end. Henrik Carlsen
I’ve never built one, but a close friend has many times. This is how he described it to me. Two people with shovels. throw snow into a pile. The bigger the pile, the bigger the cave. The act of the snow falling onto the pile changes its characteristics and the resultant pile gets quit firm. After the pile is completed, wait about 45min-hour (for it to solidify). Depends on the snow (powder will take longer) Poke 18in things (ski poles, sticks) into various parts of the pile to act as stops (you stop digging upward when you hit a stop). start digging. one man carving and pushing snow towards the entrance and the other getting rid of it. You want the top of the entrance to be lower then the sleeping area. I can’t remember where the breather hole goes, but I imagine its at or near the top. Maybe just widen one of the stops. disclaimer – build at your own risk. — [*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*] [*] Steve Hocevar [*] ravecoH evetS [*] [*] Calgary, Alberta, Canada [*] adanaC ,atreblA ,yraglaC [*] [*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*][*]
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In a course I took on winter shelter building with the AMC several yerars ago, about 8 different types of shelters were built and used by our group. Here’s a brief synopsis of our experience: Slit trench – fastest (and dampest) form of winter shelter. Here you dig a narrow trench in the snow and cover it with snow blocks or whatever is around. Then, wait for morning. (one person, one hour) Good for emergency use. Drift-cave – cozy, dry (relatively) and can be roomy. Takes a while (2 people, 2-3 hours) to excavate. Need a deep drift. Snow-pile cave – Lots of work required, your only option if snowpack is thin. Pile up snow, compress it, pile more, compress it, etc, etc. Then dig, dig, dig. Comfortable but not as stable as other types. Igloo – very labor intensive (3 people, 5 hours) and most appropriate for extended periods of time (eg a basecamp). Quiet, dry, light-filled, and super comfortable. Snow history effects how blocks cut, a saw is a necessity, and the first course of blocks demand great care in placement and positioning. Once blocks are up, still lots of crack-filling and interior surface smoothing work required. This course of offered by the AMC each March at Pinkham Notch. It’s well worth the money to build a shelter in the Gulf of Slides Wilderness area and then be forced to actually sleep in it! CB
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7) As the commerical says, Just do it. [This will teach the effort, the length of time it takes, etc.]
I did it. Once. It took 2 of us 4 hours to build it, and I was soaked afterward. It dripped on me during the night, and in the morning, it was warmer outside than inside. I bring a tent now. David Herberg
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It also helps to dress waterproof in appropriate places when you do it. Some folks wear a rain suit.
I have mixed opinions on this. I have never used a rain suit to build a serious cave (and I have built serious caves). I suggest doing both. I’m not interested in building caves in temperate zones but too much sweat and heat concern me (hypothermia, which in a cave with near 100% humidity, isn’t a good idea. That’s your "appropriate places." SO flip a coin on your first practice cave, or do what the physicists did in the 20s: wear a suit on MWF and no suit on TTS. And Sunday: rest. Resident Cynic, Rock of Ages Home for Retired Hackers {uunet,mailrus,other gateways}!ames!eugene Second Favorite email message: 550 Host unknown (Authoritative answer from name server): Address family not supported by protocol family A Ref: Mathematics and Plausible Reasoning, vol. 1, G. Polya
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| | | I have before been out winter camping but always sleept overnight in a tent, and | the season comes closer. So many people recommend snow caves, but I have never | seen any descriptions on how to make them. Maybe some on this forum have some | experince in doing so. Is the principle the same as building an iglo as the | eskimos. Any good ideas on how to start and where to end. | | Henrik Carlsen Although I live in Virginia, we occasionally have enough snow for building an igloo. The technique we use involves a plastic trash can for packing together snow blocks. The blocks are arranged in concentric circles of decreasing radius until the familiar igloo dome shape is completed. We also add a tunnel for access into the igloo. The structure is remarkably strong, so strong in fact that we could actually climb up the side and stand on top. The igloo was large enough to accomodate five or six people inside and myself and two friends spent the night in the structure. In Virginia, snow doesn’t stick around long, but the igloo did. Long after the snow had melted, the igloo stood in the grass until finally, it caved in. – Bill Miller
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Although I live in Virginia, we occasionally have enough snow for building an igloo. The technique we use involves a plastic trash can for packing together snow blocks. The blocks are arranged in concentric circles of decreasing radius until the familiar igloo dome shape is completed. We also add a tunnel for access into the igloo.
Sounds neat. The structure is remarkably strong, so strong in fact that we could actually climb up the side and stand on top. The igloo was large enough to accomodate five or six people inside and myself and two friends spent the night in the structure.
Moisture is a big question in my mind. Can your warm bodies raise the temp enough to get the ceiling dripping? Does the moisture from your breath recondense on the ceiling? Would you need something over your sleeping bag to stay dry? I would guess additional snow is no problem, and lightly falling rain shouldn’t be either as if the temp is low, it will give your igloo a crunchy shell. But isn’t there a big danger of a good amount of rain making your cozy home into a slushy mess that will collapse on you? In Virginia, snow doesn’t stick around long, but the igloo did. Long after the snow had melted, the igloo stood in the grass until finally, it caved in.
Vincent, thinking about how nice a snow shelter would have been compared to a drafty lean-to one winter in the Smokies…. — "If everything had gone as planned, everything would have been perfect." -BATF spokesperson on CNN 3/2/93, regarding failed raid attempt in TX.
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+ Although I live in Virginia, we occasionally have enough snow for + building an igloo. The technique we use involves a plastic trash + can for packing together snow blocks. The blocks are arranged So that’s why I have been carrying that trash can on my backpack! I finally have a use for it! Can also double as a bear [proof] can! Even better to bring a metal trash can for cooking up large vats of camper stew surprise or exotic mixed drinks. — George Thomas
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So many people recommend snow caves, but I have never seen any descriptions on how to make them. Maybe some on this forum have some I’ve never built one, but a close friend has many times. This is how he described it to me.
[description deleted] I can’t remember where the breather hole goes, but I imagine its at or near the top. Maybe just widen one of the stops.
[Totally naive question by someone who's never camped in the snow]: What if it’s snowing? What does one do about snow clogging up the breathing hole(s)? –Mike Tamada Occidental College
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