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WouterB wrote:I have a 1,4kg Jack Wolfskin Gossamer. Bought it over 10 years ago when I was 16. It's far from the perfect tent, but at the time, it was cheap and ticked all the boxes. I've used it in both winter and summer about twice a year, every year. It's small, light and it just works (although it takes a lot of practice to successfully pitch it in soft deep snow). It's very small, but I can change my clothes in there and even cook in the tent.

I've seen people struggle with bivy bags, and most of them weren't that much smaller or lighter. But most importantly, I know which one I would prefer.

1,4kg is pretty damn heavy for a bivy sack. My weighs around 0,4kg.

Unless I am expecting dry weather, know that there is other shelter (rock overhangs, etc.) or am planning on digging a cave, I opt for a tent similar in size/weight to WouterB's.

I actually do have a couple of pretty light 2 man tents (MSR Zoid for 3 season at a little under 4lb and a Bibler iTent for 4 season/snow at a little over 4 lb) that I can use when I'm out with someone else, or solo in bad weather. I was just wondering how practical a bivy would be for really light (under 1 lb) solo shelter if I knew there was significant chance of rain. Sounds like it's OK if fast and ultralight is an over-riding issue but otherwise not a comfortable choice in bad weather. Thanks all.

Whether or not a bivy bag is a good option in the rain depends on a lot of factors. Bivouac bags were originally designed as ultralight survival bags for climbers stuck in compromising locations by a sudden turn in the weather or to enable survival on a long trip where extra weight compromised the chance of a successful summit. They are excellent for those uses and incorporate the advantage of being able to be laid out on a narrow ledge or in a minimalist snow cave. Many ultralight trekkers have embraced the bivy as an attempt to cut down on pack weight and to move more easily through the mountains. That new purpose has stimulated many new designs in the original concept of a bivy which, in turn, introduces new complications in assessing the value of the bivy bag for general camping. The advantages of a bivy are the ease of setup, small footprint, no need for stakes, low weight (in most cases), protection against harsh weather (wind, rain, snow), protection from dew, marginally enhanced efficiency of insulating layers even in windless conditions. The disadvantages are just as real. Claustrophobic during long periods of forced use. Limited to solo use. (For two people, a lightweight tent or tarp tent provides more usable space for similar weight depending on tent and bivy design.) Problems with condensation which are more easily managed in conditions where a bivy is not actually needed. Difficulties managing your sleeping system in sustained rain or heavy snow storms. Challenges with exiting and entering,-especially in inclement weather while keeping clothing layers dry.

These characteristics of bivy bags are well known. Ultimately, the balance between advantages and disadvantages depend on the end use and expected conditions. If the bag is being used as an emergency shelter, many of the discomforts of the bivy bag are mere inconveniences. Many of us have had experiences in the outdoors where conditions turned bad on us for one reason or another. Having a waterproof breathable cocoon to wait out a major, unexpected storm or to survive an injury until rescue would be a very valuable piece of kit. Using the bivy bag for fair weather camping is a matter of personal taste. The lure of sleeping under the stars is powerful. I have spent many nights in deserts or the often dry conditions of the Rocky Mountains using only a sleeping bag or a sleeping bag with a large groundsheet that could be draped over my bag during nighttime rainstorms. A lightweight bivy bag only adds extra insurance to the experience. However, when wet, turbulent weather is expected, as anticipated in the original post, the mindset of the camper is paramount. How much inconvenience are we willing to put up with for the advantages of sleeping in a bivy? We may have to put up with the straight jacket effect of a bivy bag for extended periods of time. I have had to wait out storms for 36 hours in a tent before and I have a friend who had a similar, but multi-day experience in one of the larger bivy bags. I was grateful for my tent and my friend never took her bivy bag again for an extended backpack. Three solid days trapped in a bivy bag was not an experience she wanted to repeat. On the other hand, if we are willing to extend our experience with a lightweight tarp, we expand our comfort options though we begin to subtract from the minimalist advantages of the bag. With just a bag, can we keep the rain off of our faces? Sure. Zip it up at the cost of more internal condensation. Or sleep head end under a thick spruce tree. Or pitch a mini tarp just over the head area. Or drape a Gore-Tex shell over our heads while we sleep. Or sleep on our tummies during a storm. If the adventure of sleeping out with minimalist gear is strong enough that these are merely minor inconveniences to you, then go for it. If you value your sleep and comfort more, then bring an ultralight tarp tent for those bad weather forecasts and save the bivy bag for emergency use or for more ideal conditions and those those just-in-case scenarios.

WouterB wrote:I have a 1,4kg Jack Wolfskin Gossamer. Bought it over 10 years ago when I was 16. It's far from the perfect tent, but at the time, it was cheap and ticked all the boxes. I've used it in both winter and summer about twice a year, every year. It's small, light and it just works (although it takes a lot of practice to successfully pitch it in soft deep snow). It's very small, but I can change my clothes in there and even cook in the tent.

I've seen people struggle with bivy bags, and most of them weren't that much smaller or lighter. But most importantly, I know which one I would prefer.

This wolfskin page says it's 1.75 kg, not 1.4. That's a just a big difference, but never mind, that's WAY worse than half of a 4 season tent - a Nemo Kunai (a decent tent, not fantastic) is 1.96 kg plus ground sheet. But that REALLY does the job, unlike many tents (see below).

This conversation has been super-useful, thanks to all participants. I'm looking into lightweight shelter options, and I note:
1) lightweight tents are usually all mesh, and so are piss-poor in wind, which is really most of the reason for a shelter in the first place. Especially in the mountains. (OK, except for the rain problems mentioned above.)
2) Ultra-light (UL) single layer tents tend to be the same: to avoid condensation, they have large mesh panels, sometimes on two sides. This is, again, not so hot (pun intended) in the wind.

Last weekend, I said, "heck with it", and tried to sleep out in high summer sierra conditions with just my light down bag and a ground sheet. I froze on the freak cold night, and felt every breath of air motion. If I had had a bivy sack, it would have blocked the wind. So I was thinking, maybe sacks are a good way to go.... but after reading this, no thanks.

-TPC