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Like a hardshell jacket for your sleeping bag.

From exposed ledges to drippy snow caves to lakeside granite slabs, the Marmot Alpinist Bivy provides waterproof breathable protection for you and your sleeping bag. With MemBrain shell fabric and fully taped seams, moisture stays out and warmth stays in. The highly compressible design takes up minimal space in your pack so you can maintain your light-and-fast ethic.

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Marmot Alpinist Bivy

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Here's what others have to say...

I plan on using a Bivy for winter camping,...

I plan on using a Bivy for winter camping, in a tent only. First for a little extra warmth, and second for keeping any moisture off my down sleeping bag ( snow from other gear and frost from the inner side of the tent in the morning ) also a little extra protection for the sleeping bag itself. Will this Bivy keep my sleeping bag dry on the inside from the heat and moisture from my body. It will always be open and I will not be breathing directly into the Bivy it's self.

Any help is greatly appreciated

Responded on

I have this bivy and too many different bag combo's - if your looking for extra protection, if you can spend your $ on a bag with moisture resistance or treat your current bag. For a vapor / moisture barrier, an extra pound is lots to carry speaking from experience.

If your sleeping in a tent and I assume you have a properly rated bag yet are concerned with MOISTURE during winter outings, rethink how you are setting up your tent to get MORE ventilation / airflow to avoid moisture issues. That said, all other considerations aside, yes, this bivy will help keep your bag dry but with significant weight and volume penalties that gotten around with a little extra care and buying a better winter bag.

**If you suffer from excess frost/moisture and if your looking at this as a solution to avoid needing to increase the amount of ventilation in your tent, it is going to deliver lackluster results at best.

Unanswered Question

What is the purpose of this if to breath...

What is the purpose of this if to breath it needs to be open? If its raining or snowing how are you supposed to stay dry if the zipper has to be open for breathability? Does that not defeat the purpose of this entire line of products, unless you have a handy alcove or snow cave?

Unanswered Question

Would this be a good choice for winter...

Would this be a good choice for winter camping in Montana?

my main concern is the breathability of...

my main concern is the breathability of the fabric since i will be using the bivy under a tarp or in a snow cave. any ideas how the marmot membrain works compared to eVent or the gore-tex respiration?

Best Answer Responded on

In cold winter, this will serve you better than an air permeable fabric because it will add a little warmth and your body heat will force out moisture, whereas with an air permeable fabric like eVent or exchange lite, the mousture will quickly freeze on the bivy, blocking the pores and eliminating breathability. Basically, all that to say that for sub freezing weather, get this, otherwise, you'll be better served by eVent (gore tex exchange lite is simply rebranded eVent).

does anyone rock their sleeping pad inside...

does anyone rock their sleeping pad inside of the bivy or do most people put it underneith the bivy

Responded on

The point of a bivvy sack is that you put your sleeping bag inside. The Alpinist is supposed to be breathable enough that your down bag won't soak through, and if it's synthetic, it shouldn't be an issue.

Best Answer Responded on

idk if you were replying to my question, but if so re-read and try again. i am inquiring about sleeping pads.

Unanswered Question

anyone have a picture of this thing packed...

anyone have a picture of this thing packed up in the stuff sack?

5 5

Best bivy I have owned

Any bivy is going to have some condensation, this is no exception. This bivy is super light, durable, and exactly the minimalist gear I need to stay dry in rain.

what is the size of this thing?

what is the size of this thing?

Responded on

Heres the Specs:

Colors:Alert (9321)
Maximum Weight:15 oz / 0.4 kg
Minimum Weight:14 oz / 0.4 kg
Dimensions:8x36x86in / 20x91x218cm
Packed Size:6 x 9 in / 15 x 23 cm
Tent floor Material:40d 100% Nylon Ripstop 3000mm W/R, F/R
Tent canopy Material:MemBrain®Strata™ 100% Nylon Ripstop 2.2 oz/yd

Keeps me dry!

Keeps me dry!

I love this bivy. Of course, as with every bivy, you can have problems with condensation but I don't tend to have much of a problem with mine. I have slept in mine for two separate weeks of straight rain and cold and the Marmot alpinist bivy kept my down bag dry and insulating both times.

4 5

Great for lightweight camping

I love this bivy! it packs super small, its super light, and insanely water repellant. the only problem I had with this bivy was the condensation that I woke up with, but other than that its fantastic!

4 5

Straight Shooter

A great super light no frills bivy that packs down to nothing and is pretty roomy. I breathes better than other ultra light sacks I have used, but expect some sog in the morning in all but the coldest climes. Great construction and ready for a beating.

4 5

Good bivy, with a few kinks

I've used this bivy in two of the most extreme conditions I could find on a college budget. My brother and I snowshoed into Snowy Range in February where we encountered 50 mph winds on top of -10 degree temps. I also used it throughout Wyoming this summer encountering multiple rainstorms, one of which got the best of the bivy.

My first praise is that the Marmot Alpinist Bivy is very roomy. I'm 6' tall about 180 lbs and had plenty of room for camera equipment, boots and and my clothes. It has enough room that I'm working on fabricating a lightweight skeleton to add headroom and keep rain from pooling on top of my face once I'm tucked in for the night. I wouldn't hesitate to nestle up with my pack in the Alpinist if the conditions demanded it.

The bivy was also very durable and light. I consider myself pretty careful when it comes to gear handling, but I wasn't afraid to used it atop my pad, which rested on a bed of pine needles and branches on my snow hike.

One of my concerns, though, was with the size of the bivy. Unless you are camping on a perfectly flat surface or in a trench like I dug in the snow, the bivy will allow plenty of room to roll and slide. I found the zipper hard to find some mornings as it was often underneath me.

Another thing that caused some concern was the breathability. There are plenty of reviews out there that say this is a strength. However, I found the bivy got quite stuffy in about 15 minutes - enough so that it made me worry about suffocation. It's definitely possible with this bivy - hence the multiple warnings on the tags.

I would have liked screen or mesh integrated into the zipper system or underneath the hefty rain flap. The 50 mph winds I endured up in the Snowies kept this bivy well ventilated, but before they picked up there was considerable condensation inside.

While camping at Sinks Canyon in Wyo., the bivy held up well against a downpour. Unfortunately, the size of the bivy and the zipper combined malfunctions to create a sink of it's own, directing most of the rain into my bivy.

Looking back, keeping the zipper shut further would have been beneficial. While the three zipper heads allow you to have two smaller holes instead of one big one, the condensation that built up inside the bivy was enough to lightly hurt my down bag anyways.

I'm hoping that whatever skeleton I'm able to come up with will keep a good amount of the condensation away from my bag and allow the rain flap to be used to it's full potential.

With integrated mesh, this would be a five star bivy hands down. With some fine tuning, it will be the only shelter I need.

5 5


this thing is awesome! turns a 15 degree bag into a 0 degree! it survived the grand targee bluegrass festival, no matter how drunk you are you cant hurt this thing.

2 5

Strange Zipper

While this bivy is light and packs nicely, the zipper placement is very strange. It starts from the middle directly above your head and goes down to your shoulder.

Responded on

umm, no. not a strange placement at all, seeing that it starts up near your head(for ventilation?!?!) and goes well past your shoulder down the side towards your waist.

how are you supposed to breathe with it...

how are you supposed to breathe with it zipped all the way up? is there noseeum mesh?

Best Answer Responded on

You can't. You need to leave the zipper partly open to maintain airflow. There is no mesh, but it has a generous storm flap, and the 3-zippers allow for two any-size openings.

5 5


This is the newer version of a bivy of mine that I have used extensively over the years, bivying in it for 21 days, well -1 night when I crawled into the tent with my friends. Anyways amazing, breathable, my sleeping back is never soaking and I have slept many a comfortable night in the snow. perfect for light and fast ski traverses. Packs small.

Do I need a tarp for this bivy (or any...

Do I need a tarp for this bivy (or any bivy) when I snow camp? Looking for something to replace a tent for April/May/June ski tours (might also use it for added warmth in a tent in the middle of winter). Breathability and weight are main factors. Not planning to use in wet/stormy weather. Thanks!

Responded on

won't need a tarp. the bivy is waterproof and uses a heavier 40d fabric on the floor. Weighs under a pound and is highly breathable. Great choice for going light on spring/summer ski tours.