Alpine AscentShell Bivy
Why We Like The Alpine AscentShell Bivy
"Less is more" doesn't always ring true, but the Alpine AscentShell Bivy packs as much as possible into a small alpine shelter. On our lightest ascents into the wilderness, this bivy offers serious protection in all four seasons. Outdoor Research's Helium AscentShell membrane keeps us secure in unruly weather, and it boasts breathability that ensures our outdoor comfort during the hotter months as well.
Details
- Four-season bivy for alpinism and solo backcountry adventures
- Helium AscentShell floor and fly keep rain, wind, and snow at bay
- Mesh screen allows more airflow on hot summer nights
- Large, step-in opening offers easier, more comfortable entry
- Single pole design makes setup fast
- Packed only weight barely exceeds one pound
- High volume toe box and extra headroom for gear storage and roomy comfort
- Item #ODRZ8NB
- Responsible Collection
- Bluesign Approved
- Material
- [membrane/laminate] Helium AscentShell (3-layer), [face fabric] (fly) 30D nylon, PU coating, (floor) 40D nylon, TPU coating
- Poles
- 1
- Ventilation
- mesh canopy
- Seams
- fully sealed
- Floor Dimensions
- 83 x 28in
- Floor Space
- 79 x 32.5 - 22 x 19in
- Packed Size
- 3.5 x 12.25in
- Trail Weight
- 1lb 0.8oz
- Packed Weight
- 1lb 2.6oz
- Activity
- mountaineering, backpacking, ultralight backpacking
- Manufacturer Warranty
- lifetime
Reviews
Q&A
What do you think about this product?
Overall Rating
4 based on 38 ratings
Review Summary
Customer Images
View
Selecting an option will reload the available reviews on the pageFebruary 7, 2025
The ability to not suffocate on my bivy while staying dry is worth every penny. The bivy will also trap more heat when temperatures drop. I’ve been hot in a 0 degree bag in single digits.

Originally reviewed on ExpertVoice.com
January 11, 2025
Durable, prep for rain…
The weight of this bivy is phenomenal when compared to full body tents. At 18 oz (1lb 2 oz), this breathable (albeit ventless) shell is a great alternative to a heavy weather proof tent when you know there will not be inclement weather. With only 3 stake points, one pole and the body (no footprint needed), you will never notice this piece in your pack. The set up is rather quick and easy. Inside, you may feel cramped but once asleep, you won’t notice. I was able to store my shell jacket, shell pants, a book, a towel, warm gloves and a puffy and STILL had plenty of headspace. I use the Thermarest NeoAir XLite Max SV. This a rather wide sleeping pad and still fits nicely in the bivy. So if you are concerned with your pad fitting, if it’s smaller than this you will be fine because any bigger may not. The ugly: throughout one whole night of rain in the backcountry of Ouray, CO the inside of the bivy was dripping and coated my sleeping bag with a nice layer of moisture. Since my bag is prepared for that (dri-down and DWR coating), I myself was never wet and slept through the night. Immediately when you open the bivy, if it’s raining, the rain will enter your sleeping space since there is no vestibule. Overall, I think the construction for the weight, breathability and ease of set up/take down, leads me to recommend this bivy for “dry weather backpacking” to any ultra light adventurer.

Originally reviewed on ExpertVoice.com
December 19, 2024
Bigger than the interstellar! Made for adults.
This is my third OR bivy which I use for alpine adventures. First was the Helium, great size but did not like the clam and it would trap moisture. I replaced the Helium with the interstellar. The interstellar was a great idea but was too small and tight, it would crush my lightweight quilt and could not turn over, more coffin like. The interstellar also had too many zippers which you would have to sort to escape. This Alpine Ascent Bivy is closer in size to the Helium but with the top flap zips for stargazing/venting. The Alpine A Bivy is what the interstellar should have been. Looking forward to using this in the spring. Gave 4 stars since I have not been able to field test.
Originally reviewed on outdoorresearch.com
December 1, 2024
Good size
Provides adequate space at shoulders and face. Well constructed. Used bivy for 5 nights inside a larger tent on a glacier north of Hanes AL during an AT trip.

Originally reviewed on ExpertVoice.com
November 30, 2024
Almost Great
- Familiarity:
- I've used it once or twice and have initial impressions
Don't get me wrong, I love OR products. And this one is ALMOST one of the greats. But designers cut the handle off the toothbrush trying to get a flyweight bivy even lighter. Two big problems: the K-Mart quality pole, wrestling match to insert or remove, and the shoelace-weight guyout anchors--of which there are not five, but two. I am having five anchors added to make this a shelter you can walk away from without worrying that a breeze will flip it around itself, or tear it free. Back to the drawing board, OR! Shell fabric: fantastic. Cut: great. Pole: what WERE you thinking? Anchors: a joke.
October 29, 2024
Great Bivy for lightweight excursions
I bought this bivy for lightweight camping with my unit in Alaska. I had first bought the Helium Bivy, but issues with winter equipment made me buy this one as well. My favorite part of this is that it can hold thick winter sleeping pads that are R level 7 or higher and have a heavy below zero degree (F) bags and still have room above my head to help breathing. There are also three zippers along with the bug net. This helps vent it so there’s fresh air and prevent condensation in cold nights. There’s also additional room to keep boots or small items in the bag with you. Overall, great bivy for cold weather and lightweight backpacking.

Originally reviewed on ExpertVoice.com
October 25, 2024
Perfect Bivy - Cozy, Warm, and Waterproof Nights
Excellent bivy. Warm, cozy, comfortable, breathable, and waterproof. I regularly use this bivy for solo motorcycle trips through the back country. I have used it in rainy, snowy, hot, dry, dusty, and cold weather. I recommend using a blow up pad with this bivy because it helps the structure to stand up and it tightens the fabric, which improves shedding water. I use a ThermaRest NeoAir XLite rectangular pad and the bivy feels slightly more tent-like with the pad inserted. Using a good air mattress also eliminates the need for any staking. I do not use any ground tarp or cover and I have not seen the need for a ground tarp. I have slept through torrential downpours and stayed completely dry. It sets up in a couple of minutes and packs up just as quick. It took me a minute to figure out how to install the hoop pole but once I found the insert pocket, it was easy from there. A bivy is not a tent and there are trade offs. For example, if I knew it would be raining every day of my trip, I would bring a tent instead so that I could have more real estate when seeking cover from the elements. However, this bivy is perfect when you know the weather will be mostly favorable and you need to travel fast and light. Sleeping under the stars in the bivy and the feeling of being completely swaddled in your warm and cozy shelter are my favorite things about this bivy.
Originally reviewed on outdoorresearch.com
September 13, 2024
My Favorite Bivvy that I own so far, easy to get into, large opening. It does run pretty warm, so you might want to have a layer between you and the shell.

Originally reviewed on ExpertVoice.com
June 21, 2024
Durable, not waterproof
The weight of this bivy is phenomenal when compared to full body tents. At 18 oz (1lb 2 oz), this breathable (albeit ventless) shell is a great alternative to a heavy weather proof tent when you know there will not be inclement weather. With only 3 stake points, one pole and the body (no footprint needed), you will never notice this piece in your pack. The set up is rather quick and easy. Inside, you may feel cramped but once asleep, you won't notice. I was able to store my shell jacket, shell pants, a book, a towel, warm gloves and a puffy and STILL had plenty of headspace. I use the Thermarest NeoAir XLite Max SV. This a rather wide sleeping pad and still fits nicely in the bivy. So if you are concerned with your pad fitting, if it's smaller than this you will be fine because any bigger may not. The ugly: throughout one whole night of rain in the backcountry of Ouray, CO the inside of the bivy was dripping and coated my sleeping bag with a nice layer of moisture. Since my bag is prepared for that (dri-down and DWR coating), I myself was never wet and slept through the night. Immediately when you open the bivy, if it's raining, the rain will enter your sleeping space since there is no vestibule. Overall, I think the construction for the weight, breathability and ease of set up/take down, leads me to recommend this bivy for "dry weather backpacking" to any ultra light adventurer.

Originally reviewed on ExpertVoice.com
June 21, 2024
Durable...not waterproof
The weight of this bivy is phenomenal when compared to full body tents. At 18 oz (1lb 2 oz), this breathable (albeit ventless) shell is a great alternative to a heavy weather proof tent when you know there will not be inclement weather. With only 3 stake points, one pole and the body (no footprint needed), you will never notice this piece in your pack. The set up is rather quick and easy. Inside, you may feel cramped but once asleep, you won't notice. I was able to store my shell jacket, shell pants, a book, a towel, warm gloves and a puffy and STILL had plenty of headspace. I use the Thermarest NeoAir XLite Max SV. This a rather wide sleeping pad and still fits nicely in the bivy. So if you are concerned with your pad fitting, if it's smaller than this you will be fine because any bigger may not. The ugly: throughout one whole night of rain in the backcountry of Ouray, CO the inside of the bivy was dripping and coated my sleeping bag with a nice layer of moisture. Since my bag is prepared for that (dri-down and DWR coating), I myself was never wet and slept through the night. Immediately when you open the bivy, if it's raining, the rain will enter your sleeping space since there is no vestibule. Overall, I think the construction for the weight, breathability and ease of set up/take down, leads me to recommend this bivy for "dry weather backpacking" to any ultra light adventurer.
Originally reviewed on outdoorresearch.com
Do you have a question about this product?