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Bivy on Whitney near Trail camp

I took the BD winter bivy out for a test run with my Marmot 40degF on Whitney last weekend and with my Mountain Hardwear 0degF near New Army Pass two weekends before; both times I used a Therm-a-rest NeoAir. While the bivy is nice and lightweight, it doesn't breathe perfectly and is a little tight with the air mattress and 0degF bag; otherwise it is perfect.

Bivy on Whitney near Trail camp


    I used this in the North Cascades in February during a snowstorm up 6000ft and it was absolutely horrible. Not waterproof, not windproof, and should NOT be considered a "winter" bivy, let alone a bivy at all. It's thinner than tent material and super light-weight, but that is not always a good thing. Get another bivy, not this one.

    One advice: Seal its seams

      This Bivy sack does what it's meant to, nothing more. It is amazingly light and is designed to keep you warm and dry while sleeping mostly ABOVE the snow line. i.e. when it is cold and snowy and rain is not your biggest concern. The biggest advantage is its highly breathable fabric (my experience, I see some controversy here), which is priceless as I use a down sleeping bag. Its disadvantage are the almost "transparent to water" seams, hence I strongly recommend sealing the seams for true water resistant (NOT waterproofness) If your are after water proof, Gore-Tex, and the like, this is not your sack.

      Very light but no good

        I agree with other reviewers. This thing doesn't breathe. The inside was wet from condensation after 1 night in a snow cave. Talked to an R&D guy for Kiwi company Macpac who tested Epic fabric way before BD used it. The verdict was "not the most breathable fabric around..or the most waterproof ... Ok for N America dry snow but not kiwi wet snow."

        Lightweight, simple, inexpensive

          I bought this as an emergency bivy for backcountry skiing. It is a great little bag, once I'd consider taking with me on a trek where I might have to do an emergency sleep out overnight. Very small and light, not many extras, no zippers, but certainly a great product for its design, also a nice way to increase sleeping bag warmth rating.

          Misery in the Columbia's

            This item performed terribly for me. I used it on 2 overnight ski tours in the Columbia mountains of BC - both times getting my sleeping bag soaked from condensation. I also used it for an overnight well below the snow line and above freezing temps, and it still filled with condensation. This thing does not breathe at all, regardless of temperature, inside or outside of a tent. It sucks, which is a shame as I am normally a huge fan of Black Diamond gear.

            Did not work for me

              Pros: This bivy is light and simple, minimal design.
              Cons: Small, tough to get into and out of, poor quality.
              I tried the Black dimamond and the Mountain Hardwear Conduit SL, sent them both back and got the Mont Bell UL Gore Tex Wide and Long (8.25 oz including stuff sack). Love the Mont Bell.

              Not for me

                I was looking for a light, Bivy/Bag Cover mainly for emergencies but functional as a bag cover for wet nights out, or in a snow cave/shelter etc...Pros: simple, light, cheap$. Cons: Hard to get into and out of, strange/dorky zipper, not seam sealed, seemed cheaply designed and assembled. I also tried the Mountain Hardwear Conduit SL which was small (I'm 6'/200lb) and heavy. I returned both of them. I got/love/highly recommend the MontBell UL Wide/Long Gore-Tex, seam sealed Bag Cover. Just what I was looking for, and mine weighs in at only 8.25oz including stuff sack.

                Under the stars...

                  I spend 6 months a year sleeping under the stars. I don't like tents. I use to freeze in my sleeping bag in the spring and fall months. When I got the winter bivy sack, it added the extra 10-15 degrees I needed to stay warm without a tent. Just by blocking out most of the wind, that a tent would do. It is small and very light weight.

                  thank you! not everyone is a high altitude whiner who is overweight and then tries to save 4 oz and complains. alot of us ultralighters do it as a lifestyle, not a heroic adventure that whisks us off to exotic lands and world famous/feared peaks. this bag works fantastic as this reviewer said. just dont "buy" into lightweight. get creative. add some DIY and live less frustrated, and plenty comfortable. great review. thats what i got it for, use it for, and it performs fantastic.

                  A Night in Red Rocks

                    I got this sack for a trip to Red Rocks thinking it might come in handy if I went in to the backcountry. Little did I know I would be using it the first night because we were short one tent. It kept me dry and extra toasty even though the outer shell was wet with dew. It also packs insanely small. Darn good sack at an awesome price!

                    Light and useful, with limitations

                      Used for winter camping in -10 to 20F.

                      -Excellent, light protection from elements for bag.
                      -Above-average breathable.

                      -Single zipper across shoulders is challenging for inserting pad and bag(s), especially when freezing (no side zip).
                      -No face panel; zipper slit not ideal for external visibility or ventilation.

                      Great sack

                        Used the bivvy bag with a PHD bag in Austria at minus 26C and it performed brilliantly. The bag is VERY light, but still surprisingly strong. You may need to pop a bit of string onto the Zip puller to operate with gloves, but otherwise a very good bit of kit.

                        BD winter bivy

                          The weight and compression are great. I used it in heavy rain, it helps about as much as it weighs…zero. Not that it is designed for that anyway. Otherwise it does a fantastic job of blocking morning dew and snow won’t stick to it either. It’s excellent when used with a shelter, I'm able to use my down bag more often thanks to this! The tiny zipper is a pain with cold/wet hands, and the material has a "static cling" effect when damp. Great for the minimalists! BD has great customer service too.

                          Black Diamond Bivy Sack

                            This is one of the lightest, super compact (size of a soup can) bivy sacks out there on the market and for this price it is a steal. Water resistant, tear resistant and added warmth to any mummy sleep system, it is great for that unexpected downpour or just by itself on those warm summer adventures. A must have for the avid outdoorsman(woman)-- outdoors-person!

                            I wanted more than bare bones!

                              I'm sure this is a great bivy for minimalists, although there are a couple of items you may want to consider before ordering. All seams are untaped and there are perpendicular seems running across the top of the toe box area (top & bottom) as well as down the sides. The shoulder zipper is not nearly as convenient as a full length side zipper. At 55% humidity @ 55 degrees, it seemed to collect condensation as redily as a Mountain Hardware SL conduit bivy.


                                This bivy packs up small enough to put in a pocket! Condensation wasn't a problem for me when I used it, but it was dry. It's just a handy thing to have around because it takes up so little space and does exactly what it was designed to do nothing more and nothing less.

                                I have had many ruined campouts with flooded...

                                I have had many ruined campouts with flooded tents or very rainy conditoins. Would this bag be considered "Waterproof"? And I would also like to know if it would be good for heavy rain.

                                I am thinking about getting a big agnes 0...

                                I am thinking about getting a big agnes 0 degree and combining it with a bivy for winter camping in the rockies of colorado. I am an avid AT skier but am wanting to get into longer trips. Would this bag/bivy idea be ok for the cold winter high country? How much warmth does a bivy add?

                                I think the ground is really cold in the winter and I cant imagine this thing actually keeping anyone much warm other than a bit of wind chill and water, but I wouldn't expect much more than 3 degree's advantage. They should have it engineered and tested, with specs for those who'll actually be using this type of gear to survive out there.

                                is this a good bivy that will protect...

                                is this a good bivy that will protect against the elements when raining and will hold a person and a sleeping bag? Would this be an okay bivy for ultralight weeklong backpacking trips?

                                Best Answer

                                My personal experience is that it is superlight and pretty waterproof. I have spent a few nights in light rain in it and been dry. I would recommend putting the seamsealer that comes with it. If you want something totally waterproof I could recommend the It is fully waterproof. The Winter bivy is superlight and compact but isn't designed for week long rainy backpacking trips. I can understand any apprehension on your part. It's like being on a rope for the first time. Trust your gear. It will perform just fine.