Bivvy Bags

A bivvy(from bivouac) bag is a cover that goes over your sleeping bag and protects from the elements. These come in a variety of designs with almost all outdoor brands having their own take on the classic tube design.

I own two bivvy bags, an Alpkit Hunka in an attractive shade of red and a British Army surplus in olive green. The Alpkit one cost £33, weighs 288g and packs down very well. It is made of a material similar to gore-tex but lighter and is just big enough for me (6ft2 and fairly lean). It is available in a larger size for £50, I would recommend this for anyone over 6ft2 and anything other than stick thin. I like this bivvy bag for anything involving a large walk in (it is fairly light). It has the simplest sort of hood, a drawstring which leaves a minimum hole the size of a 10p, though in better weather it is wise to leave more to prevent condensation. I have used this bag on a few occasions, in the Alps and Scotland and it has performed well.

The army surplus one I picked up for £10, quite a bargain. They are available online for £30-£60 depending where the British army is deployed at the time :) It is far more spacious than the Alpkit one, with plenty room at the head. The closure is also by drawstring leaving a similar hole. This bag weighs 800g, more than double the Alpkit one, however for the extra comfort and room (it is possible for me to fit a fair sized rucksack in the bottom comfortably and move about a lot more in it) it is worth carrying on a short trip. I have used it twice so far, once for a chilly bivvy under the shelter stone in the Cairngorms where it kept me dry if not warm and once in a storm-lashed single skinned tent by the Cairngorm carpark. On this occasion we were woken at 6.30 by the wind uprooting our tent and the rain driving against the skin....there was a fair amount of water in the tent by this point perhaps due to condensation, perhaps due to the skin leaking (the conditions were fairly severe). Sleep was out of the question so we took it in turns to get dressed and sprint to the car. I did notice however that the bivvy bag had kept all moisture out of my sleeping bag and droplets seemed to be beading on the surface as opposed to soaking in-a good sign. In summer or if camping on boggy/uneven ground I would lay out a bivvy bag beneath me as I did on Arran when I chose a less than ideal campsite.

Many hillwalkers choose to carry survival bags...light, orange affairs that make great sledges in winter. These are completely non breathable andwaterproof, which means that instead of being soaked by the rain you will be soaked by your own breath and sweat if you stay in one long enough. I have only seen one used once, when under the shelter stone I lent my spare to a friend to keep his synthetic sleeping bag dry in the event of condensation on the underside of the rock. Mats made the schoolboy error of breathing into his bag during the night to keep warm and when the morning came (we crawled outside and basked like lizards in the blazing sun) he was soaked. These are available for £2.50 and are useful perhaps as a spare groundsheet when cut in the right way.

It is possible to pay up to £330 and up on a bivvy bag, for example this bag by Terra Nova. Generally you are paying for ventilation flaps of some sort and lighter weight and this bag is no exception. Whether it is worth paying depends on how much cash you have and what you want to do.

Given that some people find bivvy bags claustrophobic and cramped there has been a great deal of cross pollination between tents and bivvies, with the bivvy tent or hooped bivvy being produced by many companies. These weigh more than normal bivvy bags and generally do not have enough room on the inside to be pleasant for an extended period of time or allow anything practical to be done. Think....could I spend a rainy day in this drying my clothes, looking at maps and sorting my gear?

In the US there is a tradition of using tarps for shelter along with bivvy bags, in order to allow the hood to be open in bad weather. Tarps are light and having one big enough to cover the opening is not too difficult. Some people use a hardshell to cover their opening, allowing a free flow of air and reasonable protection from rain/snow/hail. Others still turn over and sleep on their front.

Bothy bags are often used by hillwalking groups as an emergency shelter for sitting out bad weather. These allow movement but will get damp inside quickly form condensation. Pairing these up with bivvy bags seems a popular choice. These are cheap, around £30 and up for a 2 person shelter.

Bivvy bags have bee a part of climbing and mountaineering for generations and will continue to frustrate. They are however extremely useful as a shelter option or in an emergency. Having slept with and without a bivvy bag I will always carry one, just in case...or because I feel like being comfortable.