Bivy shelters for mountaineers
08 November 2008
Note: Many of these articles are very old, and although the technical information is still relevant the equipment mentioned may not be (for example a Stormy cooker was state of that art in 1995, but not in 2021).
There has been a slight shift in the upper echelons of alpine climbing over the last few years as people have looked for more protection on exposed bivvies, having found the traditional bivy sack didn’t always offer enough of a defence against the night. The problem is that if it’s raining, snowing or just windy you can’t do much from inside a bivy bag, meaning no cooking, chatting or playing chess, and there’s a good chance you’ll end up bailing sooner rather than later. Also if you find yourself caught out on an exposed mountainside, or on a glacier, with no way of finding shelter, then a night zipped up in your bivy bag can be quite fraught, especially trying to get into it without bringing the weather in with you. A survival bag by its very nature is meant for survival, meaning you can’t really do any more than that within one. What is needed is a lightweight option that extends the comfort level of the user in any situation so they can live and thrive in what would otherwise be pretty hostile situations – especially when the weather turns nasty.
The result of this has been an increased interest in the use of featherweight mountain tents (Bibler, Outdoor Designs, Black Diamond, Exped), which gives the climbing team a huge increase in protection, warmth, liveability (cooking, reading, Cumberland wrestling etc) plus they allow more ability to ‘sit it out’. A secondary benefit is that using a tent allows a lighter sleeping bag to be used, and less fuel to be wasted (plus any escaping heat warms the tent), not to mention the massive psychological benefit you gain from knowing you can sleep comfortably anywhere. At the moment it’s mainly the top end climbers who are benefiting from this new view of mountain ‘camping’ (with many of them making their own tents or ‘super bothy bags’) but I think this is a trend that should filter down over the next few years. In the past the ‘Bibler’ style tent was always seen as purely the domain of the hard climber, with its small footprint and lightweight making it ideal for adventures in the Greater ranges, but not for alpine-style peaks. Yet now with cheaper and lighter tents coming on the market, combined with new materials (like eVENT and Epic), I think that some models are now affordable enough to be considered by the types of climbers who have BUY their own gear! Probably the best lightweight mountain tent on the market at the moment is Black Diamonds First Light (around £170 if ordered from the US/1.21 kg) which is made from Epic fabric, highly breathable nylon with a DWR coating. This means that the tent isn’t 100% waterproof, but it is snow proof and shower proof (the seams need to be sealed with SeamGrip), and it’s surprising just how much rain this tent can handle, plus it’s far more breathable than any other single skinned tent on the market. Without the poles, the tent packs down to the size of an inflated crisp packet and holds two climbers with plenty of room (you could squeeze three in at a push). The best thing about this tent, and all such tents, is its tiny footprint (the space it takes to pitch it), going up ledges no bigger than a small settee. Rab is also bringing out a range of tents later in the year in eVENT based on the successful Outdoor Designs range, which may be slightly heavier, but should also be more waterproof.
One thing you soon realize when you look at North American outdoor users is their love of the humble tarp – basically a large rectangle of plastic or nylon. Many people use tarps instead of traditional tents, saying that they are lighter, more versatile and dryer (due to increased ventilation), and because they can be pitched in many different ways. The first thing that springs to mind is that these tarp fanatics have obviously never had the pleasure of a wet bank holiday in the Lake District. Never the less over the last 10 years North American mountaineers have begun to adopt the tarp concept to their own needs, producing a very practical and lightweight concept that could be of great interest to UK climbers. The breakthrough has been the availability of amazingly lightweight 30 denier ripstop nylon with silicon impregnation, which weighs in at a staggering 38 grams a square metre! This can give a 5x8 foot tarp that weighs only 200 grams but is still waterproof. The beauty of the tarp is its versatility and here are a few ways of using one:-
This method creates a traditional tent shape using either two ski poles (or sticks) or by guy points from trees or boulders (using your rope or dedicated guying cord). The ideal pitch is low to the ground to reduce the chance of rain or snow blowing under the tent, with the sides either being close to the ground or open (to increase ventilation). The ends can be left often, or semi blocked with rocks, snow or rucksacks. In a climbing situation, it’s assumed you’ll use this in conjunction with a bivvy bag.
This method requires a snow pit to be dug (shallow or deep) big enough for you to comfortably lie down, but no larger than the size of your tarp. The tarp is then secured across the top of the pit to form a roof – keeping wind and light snow out and keeping the heat in. If you have skis then these can be placed across the pit first in order to support the tarp for heavier snowfall (you can place snow on top to increase ventilation. Once in place, it’s worth placing snow blocks all the way around the edges so as to stop windblown snow from getting into the shelter.
If you find yourself on a ledge in just your bivy bag in a storm then the tarp can be used to keep the elements off you – so you can cook etc. To do this the tarp can either be secured at two points on either side of you so that most of the crap slides off you, or you can hang it from its central point – creating a kind of portaledge fly set up. There is no breath-ability in a tarp so ventilation is important (you will get lots of condensation), but it will prove a very big psychological boost in such situations.
One great thing about these tarps is that you can use them as bothy bags – giving you more flexibility over just a straight bothy design. To do this you can just pull the tarp over you and tuck it in under you. Another option is to sew Velcro along two edges so that you can form a tunnel which you can crawl into (this is the beauty of the tarp in that it’s easy to modify – adding drawcords, loops or vents where you need them).
The best thing about a tarp is that it’s like a blank piece of paper and it’s easy to adapt it to any crisis. Although I don’t expect many readers to need it in this capacity, one use is as a slide, being pitched over bivy tents when pitched on steep snow slopes (the snow slides over the tarp rather than pushing the tent off). For less adventurous uses the tarp can be pitched to the porch of a tent to give more dry space for cooking (or thrown over a tent when it leaks), or attached to the boot of your car for that dirtbag bivy, or used as an emergency waterproof – in fact the options are limitless.
At the moment, as far as I know, you can’t get the lightest tarps in the UK (not 30 denier silicon nylon anyway) so you’ll need to mail order one from either the US or Canada. The best model on the market is the Canadian Integral Designs Siltarp1, which is used by climbers such as Mark Twight, Barry Blanchard and Steve House. It weighs in at 200 grams, is 8x5 foot, and features 16 lightweight webbing tie loops sewn on the corners and edges, plus a reinforced central loop. This is the lightest option, but some people may want a larger tarp, in which case the Siltarp2 at 8x10 feet (400g) may be better. Integral Designs have quite a range of tarps and I’d recommend you check out their site. Price-wise with a strong pound, these tarps come in at around £30 and £60 before postage, duty etc. The best option for getting hold of one of these is probably to order it from Mountain Equipment CO-OP (you’ll also need to become a member), although I’m sure far sited specialist retailers will soon be stocking them in the UK.
If you decide to use a bivy tent then it’s important that you learn how to employ it effectively. One common system the ‘Fowler Style’ which has been used by Mick Fowler and his partners to great effect over many years. For this a team of two carry one bivy bag and one tent, meaning if there aren’t any spots where the tent can be pitched, then one person can use the bivy bag, while the other wraps themselves up in the tent (you may do this on a route which has no ledges big enough for two. If you find yourself in a situation where you can sit side by side, but are unable to pitch the tent, then it can also be used as a giant two-person bivy sack, either pulled up or over your heads. This is also a good technique when you just want to crash out and want the extra warmth (perhaps you’re sleeping under a bolder and there’s no room to pitch the tent). Tent pegs can be left at home when camping high, like ice axes, crampons and stuff sacks can be used instead – and if it’s rocky then larks foot slings to the guy points and use rocks to hold it in place. Using a tent/bivy bag in this combination can give you a very light and effective bivy system as light as 1.5 kg (Epic tent and bivvy bag), which is lighter and less bulky than two Gore-Tex bivy bags (and also about the same price), and what more it’ll be considerably more versatile.