Winter Bivy Sacks are Light-weight Winter Shelters

Winter bivy sacks are totally different from three-season bivy sacks which are sometimes used along with a tarp for insect and splashback safety, the place rain hitting the bottom can bounce again and moist your quilt or sleeping bag.  In distinction, a winter bivy sack is meant as a standalone shelter by itself or along with a snow shelter equivalent to a trench or snow cave. Winter bivy sacks are usually a lot increased in quantity to carry winter-weight sleeping luggage with out compressing the insulation and work greatest in dry and chilly situations the place precipitation is within the type of snow.

Winter Bivy Sacks – Benefits

The largest benefit of a winter bivy sack is the power to make use of it anyplace you wish to cease and sleep. Most fashions don’t require tent stakes or tent poles and so they pack up very small which is a bonus while you wish to hold your winter gear light-weight and compact. Most winter bivy sacks are made with waterproof/breathable high materials to assist cut back inside condensation and waterproof base materials to maintain your sleeping bag and pad dry. Insect netting can also be accessible in some chilly climate bivy sacks and may be helpful once they’re utilized in spring situations when bugs start to emerge,

There are various benefits to sleeping in a water-resistant bivy sack over a tent. It’s straightforward to discover a place to place a bivy sack at evening because it solely requires as a lot house as your sleeping pad and sleeping bag. Merely unroll your bivy sack, slip your sleeping pad and sleeping bag inside, and crawl in. This makes them appropriate for sleeping on slim mountain ledges or in forested glades the place there’s simply sufficient house to lie between two timber.

There are not any tent stakes to freeze into the bottom so you will get inside directly and get heat. Being waterproof, you don’t need to lie on high of a groundsheet both, for the reason that backside of a water-resistant bivy sack is designed to maintain you dry. Bivy sacks additionally add a couple of levels of insulation to your sleep system and make nice emergency shelters for solo winter hikers, supplied you carry a sleeping pad and sufficient insulation to get by way of the evening.

Winter Bivy Sacks – Disadvantages

Bivy sacks are far more confining than tents, with solely sufficient house for you and some small private objects. You possibly can’t actually do something inside one besides hearken to podcasts or fall asleep. It’s awkward to alter out of your moist garments or placed on dry garments inside relying on the kind of bivy sack you might have, it may be rattling exhausting to place in your boots, even to go for a pee at evening. There’s no place to retailer your backpack and the remainder of your gear can be totally uncovered an evening with none cowl.

Bivy sacks are additionally extra susceptible to inside condensation than a tent, even when manufactured with waterproof breathable supplies. You’re greatest off holding them open or unzipped at evening to cut back the temperature differential between the within of the bivy and the skin which causes condensation to kind. Tent condensation happens for a similar purpose however tents have higher air flow and extra quantity, so it’s simpler to maintain your sleeping bag dry when it happens.

Regardless of these disadvantages, I’ve buddies who swear by their winter bivy sacks as a result of they’re so quick to deploy in comparison with a tent or tarp. I’ve used winter bivy sacks and might respect their strengths, however winter nights final a really very long time and it’s good to have a bit of further house to alter your garments or sleep together with your gear inside your tent. Whichever you select is determined by what you’re attempting to perform.

Comparability Desk

Sorts of Winter Bivy Sacks

There are three kinds of winter bivy sacks to select from:

1. Hooped entrance entry bivy sacks
2. Hooped aspect entry bivy sacks
3. Sleeping bag covers

There are two kinds of hooped bivy sacks: these with entrance entrances that you just slide into toes first and people that you could enter from the aspect. Each include yet one more quick fiberglass or carbon fiber rods that give form to the hood and forestall it from collapsing onto your head or torso.

The pinnacle-end of a hooped entrance entrance bivy is normally screened with a stable cowl that may be zippered closed for heat or to dam wind or rain. This design supplies good air flow to your head and helps to expel the water vapor in your breath. The Out of doors Analysis Helium Bivy is an efficient instance of the entrance entry hooped design.

Aspect-entry hooped bivy sacks normally have a zipper alongside one aspect so you’ll be able to simply get out and in of them. This design can also be simpler to vent as a result of you’ll be able to roll up the highest cowl in dry climate to cut back inside condensation. The Out of doors Analysis Alpine Ascentshell Bivy is an efficient instance of a hooped bivy with a aspect entrance.

The only and lightest weight winter bivy sacks are little greater than sleeping bag covers. Some have drawstrings that you could pull closed over your head, some have formed mummy-style hoods or easy slits above the face for air flow. Whereas not as livable or well-ventilated because the hooped bivy sacks designs described above, they do the job if you’d like a extremely compressible, ultralight climate safety to your sleep system. The MSR Professional Bivy and the Black Diamond Twilight Bivy are consultant examples of the sleeping bag cowl design.

The way to Select a Winter Bivy Sack

There are a number of options and trade-offs to think about when selecting a winter bivy sack.

Waterproof/breathable high material

Having a water-resistant/breathable high material is essential to vent water vapor and assist cut back inside condensation that may make your sleeping bag moist. Nevertheless, in contrast to rain jackets, most bivy sack producers don’t listing the laboratory measurements used to price waterproofing (hydrostatic head, abbreviated “HH”) or breathability (movable water transmission price, abbreviated “MVTR”). That may make efficiency comparisons between totally different bivy sacks tough.

Extra headroom

If headroom is essential, contemplate getting a bivy shelter with a hooped design. These bivy sacks include a versatile pole that slides into the hood to create extra quantity round your face and shoulders. The tradeoff is that they are usually heavier than extra minimal bivy sacks.

Extra quantity

Winter bivy sacks are usually excessive quantity to suit cumbersome winter sleeping luggage and inflatable pads with a excessive R-value. When selecting a bivy sack you wish to guarantee that there’s sufficient room to your sleeping bag insulation to totally loft and that it’s not compressed by having too tight a match.

Entrance and exit

It’s a lot simpler to get out and in of a bivy sack that has a zipper alongside the aspect than one which solely has a “hatch” on the head finish, to crawl out and in of. You’ll keep drier if the bottom is roofed in snow and it’s a lot simpler to placed on and take off your footwear.

Insect netting for hotter temperatures

In the event you plan to bivy in early spring when biting bugs emerge, be sure that to get a winter bivy sack with a mesh panel over the face so you’ll be able to sleep with out bugs biting your face at evening. In the event you solely plan to sleep in a bivy sack in winter or in snow caves, a mesh panel can be much less essential. For hotter climate use, I’d encourage you to put money into an ultralight bivy sack or bug shelter reasonably than a winter bivy sack, since they’re a lot cooler to make use of. See our 10 Greatest Backpacking Bug Shelters for our really helpful three-season bivy sacks.

Weight and Packed Dimension

Don’t overlook to think about the burden of the bivy sack and its packed measurement, since one of many chief advantages of utilizing a bivy sack is gear weight and measurement discount. There’s typically a tradeoff between options and weight/measurement, however some winter bivy sacks are surprisingly light-weight and compressible.

Sizing and Match

When doubtful, order a bivy sack (examine the retailer’s return coverage) and lie in it at dwelling to see if it suits. This may in all probability inform you much more about whether or not it’ll be just right for you than evaluating the specs of a number of fashions listed on-line. Test to just be sure you can suit your sleeping pad and sleeping bag inside, and that the foot field is massive sufficient to your toes.

Emergency Bivy Sacks

There’s a class of emergency bivy sacks which are solely supposed for emergency use such because the SOL Escape Lite Bivy. These are made with skinny reflective aluminized material and lack the sturdiness or breathability of the multiuse bivy sacks listed above.

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