Bivy Vs OVerbag??

[Wharf-Rat]

Hi.
Which winter system would do a better job at adding insulation, keeping my main bag free of frost and condensation and be light enough to pack up small?

I am starting to think OVerbag, but i just wanted to see other peoples thoughts and systems of their winter ski setup, Sans Hut….

[Matt J]

My take on overbags is that they usually work best as part of a bag system. I think it's a great way to go if you are buying your first bag and want the ability to layer for different seasons. It may be worth saying that this can be done with any bags IMO. My first sleeping bag is still in service but is little more than a blankey at this point. I do sometimes take it as it weighs so little that putting it inside a thirty degree bag can be the difference between getting some sleep or not.

For true winter conditions I think it's important to go as warm as you can afford and carry. Nothing worse than a storm worsening and staying up all night because you can never get warm enough to sleep. For that reason I also prefer a light single wall shelter to a bivy. I like being able to dress or melt snow out of the wind. My last two sleeping bag purchases have been down bags with a water resistant coating on the top of the taffeta. The added water proofness is nice on multi-day trips where you can knock the frost off in the morning and it's virtually dry by the next night. I pretty much only carry a bivy for emergency purposes and so have bad memories of ever sleeping in one.

If you build a snow cave or igloo then the waterproof layer on the bag is perfect and neither a bivy sack or overbag is needed. If it's an emergency bivy in the snow then I would at least try and dig out a trench and build a wind break and a good bivy bag could be the difference in staying dry and comfortable or not.

It's important to know your own tolerance for space limitations when buying a bivy sack. The tripod over your face is clutch for some people. I think you'll probably have to give a little more detail about the type of adventure to get better advice. Whatever you decide, good luck!

[BillyFromTheHills]

If you're in a tent, overbag will do the job and be lighter/smaller.

[cesare]

If you are using a bivy sack in winter, you might as well use a vapor barrier as well. Your down bag with a simple envelope bivy and a VBL will pack smaller and weigh less than two sleeping bags.

I suggest the VBL because it gives you zero condensation issues and keeps your down from picking up moisture over time from your perspiration and respiration. It has to be pretty cold to justify IMO.

Some other tricks to extend the warmth of your bag include:

• Wear down booties and a down hood if you're a side sleeper in your bag.
• Bring a Nalgene full of hot water to bed with you. Wrap it in a mid layer and put it on your belly to keep your whole body warmer or between your thighs if your feet are cold. By the time it isn't helping much anymore, you are probably ready to get up and pee anyway.