Bivies look like a no-brainer if you want a light shelter for an overnight tour, given their low weight and tent-like look.

If you don’t know what you’re getting into, you may come away thinking the no-brainer was you…

Depending on how you go, you may love a bivy (as I do) or hate it.

It all depends on your needs and desires – and ability (and wish) to deal with discomfort.

Pros and Cons of Bivy vs. Tarp vs. Tent

You could, of course, also consider going without a shelter you have to carry, with a tarp or with a tent.

There are reasons that speak for all – and I want to speak for my preference for a bivy, of course:

Bivy vs. No-Shelter

A bivy provides more protection than cowboying it (just sleeping under the stars with nothing but mattress and sleeping bag).

The reason I don’t just go with such an approach, light though it may be, is that I usually move in areas where there are mosquitoes, ticks, and other insects.

The last thing I’d want to do is cover everything but my face, offering it as a sacrifice to anything that wants to suck my blood or get in my eyes during the night. (That I usually go on such outdoors tours with my hard contact lenses that need to be taken out for the night only adds to the desire to have my head protected at night.)

Bivy vs. Tarp

For the same reason, the often-beloved tarps don’t work for me; I don’t only want my body protected from rain, I want to be a bit more cocooned.

A bivy is just that bit more protective, if less breathable, than a tarp.

In addition, when I am somewhere up a mountain, I don’t find trees to tie a tarp to. Trekking poles would work but turn the tarp into a sail when it’s windy – and it’s usually windy where I go.

Thus, I find a bivy more versatile when it comes to where it can be used; all it takes is a piece of flat ground large enough for the bivy itself.

Bivy vs. Tent

A tent gives more comfort for sleeping and lounging around, but has a higher weight that you have to carry around. It usually takes longer to pitch it, even if it is a free-standing tent, and more space is required.

Given my desire for shelter, a tent would be great.

If it’s a freestanding one, it would have less of a need to be pitched properly than even the bivies that I like.

A tent would be more prone to catching the wind than a low-profile bivy, however.

The Thing about Bivouacking

And frankly, being low profile is important for me also because I sometimes end up in places where bivouacking is tolerated and legal if necessary… or only tolerated.

I will make sure to leave no trace; that is something I pride myself on, but I may well have been in situations where my bivouacking was, simply put, illegal.

It’s not to get away with something illegal that I prefer a bivy over a tent, however.

I will do planned bivy nights where they are allowed; illegal ones may come about when I want to do tours that go overnight, but end up having to crash somewhere because I just can’t go on.

There have been situations like that when I just slept in running gear on a roadside (well, forest trail side), but I will typically have brought mattress, sleeping bag, and bivy on the off chance I need those in such situations, when I go up a mountain somewhere.

What Sort of Bivy Are We Talking About?

We also need to clarify what we mean by a bivy.

There are bivy bags for emergency shelter that are not much more than a bag. I have heard of people who went for lightweight and cheap versions by simply using a garbage bag over their sleeping bag!

For truly lightweight adventures, a sleeping bag with waterproofing or with such an (emergency) bivy bag is the lowest weight and volume one could go, of course. You just have to also have a mattress.

The best – or worst, depending on your view – bivies I have found have been those made by Outdoor Research. And they have gone back and forth a bit with their offering!

Outdoor Research Bivy Shelters

The OR bivies that I am thinking of are a little more than the bivy bags that only provide a waterproof cover for your sleeping bag and nothing more.

They, especially the Interstellar (and simpler Stargazer) bivy of their earlier collection and the current Alpine AscentShell bivy and Helium bivy have one pole that keeps the bivy away from your head (at least, if you pitch it properly), and an inner mosquito net and waterproof-breathable outer for the entrance.

This combination of features means that you can use the bivy in warmer conditions with the outer cover open. That way, you are protected by the mosquito net, while you listen to the whine of insects outside in safety and watch the night sky.

If it is too cold (or rainy), you can close the shell and you are protected enough, given a good sleeping bag, even for winter nights.

Now, even if you need more warmth in winter or more water protection in rain, it is advisable not to close the bivy completely.

Bivy’s Major Problem

Even with the current materials that are highly breathable, you are likely to get condensation inside a bivy and feel like you are suffocating if you zip it up without leaving any opening for airflow.

There is little room between sleeping bag and bivy wall in most places – this is where the pole above one’s head comes into play – so that there is less circulation, more condensation.

A bivy simply is a tight space; you cannot toss, often hardly even turn. Cooking while in a bivy isn’t easy, either. In rain, it would get even worse.

I have usually woken up to a bit of dampness, so if you seek comfortable nights, a bivy is not advisable; there will be issues.

And Yet, a Bivy is Great

That’s just the thing, however, I find:

My fast tours across mountains that (may) require an overnight stay or that are for a planned overnight stay on a mountain aren’t for comfortably lounging in a tent.

They are for going fast with minimal weight (or minimal essential gear, at least, considering the video gear I may well be carrying), usually into the night, until I just have to crash somewhere and want to wait for the sunrise.

Even if I plan to be on a mountain overnight, it will not be for lounging but for a camp that is as small as possible, that can be put down near a peak.

To watch the sunset, I can probably still stay outside if the conditions are good.

If not, for sunset and watching the night sky, I will have the weather-protective cover of the bivy open and only the mosquito netting up, be ensconced in my sleeping bag for warmth, set my camera down nearby on a tripod and do some astrophotography.

With the sunrise, I’ll pack up and continue.

Of course it gets uncomfortable if it is too wet all around or if condensation strikes.

In rain or a thunderstorm, things would get even more uncomfortable; a bivy doesn’t make it easy to deal with a camp stove of any kind in rain.

But again: I wouldn’t be out with a bivy for comfort.

For a planned overnighter (and indeed, for most of my tours… other than my pure running), I won’t go out when the weather is horrible. If I get caught in wet conditions, I won’t mind having some wetness as long as I was able to sleep somehow, sufficiently to continue quickly in the early dawn.

For the conditions when I will go out, for the pursuits I will partake in, it is not only the light weight and low volume of a bivy that I appreciate, I even seek the discomfort.

It still comes with the advantages I described above, of low weight and volume, easy pitching wherever I can find a patch of flat ground, fast going overall.

And that way, I love using a bivy.