Introduction
Cold hands and feet, and a chilly night’s sleep are the most common complaints we hear from participants in our guided winter treks and skills courses.
Ultralight backpackers are well-known for adding back tenths of ounces to their kits in the interest of making incremental (and often, inconsequential) improvements to their safety and comfort.
When temperatures drop way below the freezing point, a different mindset is required:
- What packs a lot of warmth for its weight?
- What sort of innovative combinations can we use to improve comfort and performance?
If I’m thinking about extending my three-season kit into very cold winter temperatures, I start thinking about three important strategies:
- Two-layer insulation systems
- Vapor barrier systems
- Really puffy stuff
Two-Layer Insulation Systems
I like to use two-layer insulation systems where the outer layer is synthetic and the inner layer is down.
Down offers the best warmth:weight ratio for the inner layer. Synthetic insulation may be useful for the outer layer to concentrate the condensation (dew) point away from the down to maintain the integrity (loft) of down insulation on a multi-day trip. This works best with a sleep system. I discuss this two-layer system more in the Inclement Conditions Masterclass.
My current cold-weather sleep system uses an ultralight 20 F inner bag (Feathered Friends Tanager CFL 20) and an outer 50 F synthetic quilt (Enlightened Equipment Enigma Apex).
Another option to consider is separate high-loft synthetic insulating layers for active use (like the Patagonia Nano-Air Light or Arc’teryx Proton LT), which expel moisture better and are more breathable, and more traditional (down) insulation layers at rest and in camp. Layer both when temperatures plummet after sundown.
Vapor Barrier Systems
I use vapor-barrier (VB) clothing inside my insulating layers to prevent moisture emanating from my body entering the down in the first place.
I’ve had good success with the Stephenson shirt which can also be used for swanky outdoor winter parties because of its timeless 1970s style. More practical designs are available from RBH, and I’ve had excellent success with all of their clothing through the years. The jacket and pants are important components of the clothing and sleep system I use for multi-day mid-winter ski expeditions, including one where I used a bivy sack for my shelter in Montana’s Lee Metcalf Wilderness where temperatures plummeted to -30 deg F.
The Forty Below Vest doesn’t offer the complete warming benefits of a full VB shirt, but it does keep my back dry while wearing a pack in the winter. Back sweat is the primary reason for that wintry flash-off chill you get when you take your pack off for a break (flash-off is the extreme chilling that occurs when your body heat is sucked away as it’s allocated to evaporate that sweat). RBH also makes a VB vest.
Vapor barriers work well for sleeping bag liners in arctic conditions. The Gryphon Taurus VRB approach is the lightest and simplest way to achieve it (it uses aluminized Dyneema as the integrated vapor barrier liner).
I also like vapor barrier liners in mittens. Hardcore ultralight hikers like to use disposable latex, nitrile, or food prep gloves under their insulating gloves, but these aren’t items durable enough for winter expedition travel and are terribly uncomfortable. Check out the RBH Designs Ultralight Mitt, a staple I bring on all of my multi-day winter trips.
Vapor barrier socks are a no-brainer for footwear – even if they are semi-permeable. I use Rocky Gore-Tex socks and write extensively about them here. RBH fleece socks (with an ultralight merino liner sock) are my favorite combination for extreme cold while wearing my current winter lightweight hiking shoes and Forty Below Overboots on snowshoe trips, or with my leather backcountry ski boots.
Really Puffy Stuff
Max has an idea of what he thinks is needed for serious winter warmth in a parka, and it’s hard to argue with him. My personal favorites are the current PhD Yukon Pullover K (we reviewed an older model here) and the Feathered Friends Helios. I like puffy pants as well, and my choice are the WM Flights.
But how about puffies for the hands?
If you’re on a budget, suffer from cold hands, and need as much warmth as possible for as little weight as possible, then the Outdoor Research Transcendent Mitt is hard to beat.
However, you’ll need to follow a few tips to get the most performance out of them:
- The Transcendent Mitts are for c-c-c-old temperatures – well below freezing. They aren’t made with waterproof materials, so rain will soak them and they will be very hard to dry out.
- I use these only at rest stops and in camp hanging out doing nothing, or while hiking in an emergency. They are that toasty. Keeping my hands warm while moving is usually not an issue for me. When I tried these during high-aerobic activity (fast hiking, carrying a heavy pack, and snowshoeing/skiing) at temperatures near zero, my hands became very sweaty in them.
- Sleep with them in your sleeping bag (as long as they aren’t too wet), so any accumulated condensation in the mitt will dry by morning (and the condensation will be transfered to the outer synthetic bag layer, if you are using a 2-layer sleep system as described earliier).
- They work best with glove liners – something like a really thin wool or fleece fingered glove. That way, when you need to perform an activity requiring dexterity (like lighting a stove), just pull your liner-clad hands out of the mitt and you have enough insulation on your fingers even if it’s cold, wet, and windy to perform fine motor tasks for a short duration.
- They are too fragile to be a “work glove” (e.g., a ski, firewood-collecting, or bushwhacking glove).
Puffies are available for the head, too. Nunatak and Enlightened Equipment offer very light options that pack a ton of warmth for their weight. My favorite feature of a clothing system that uses a balaclava (or a hooded puffy jacket, for that matter) is that I can still use hoodless bags in the winter, which (for me) are more comfortable than trying to roll around in a hooded mummy bag.
Conclusion
Staying warm in the winter isn’t easy but it’s not rocket science, either. It does require a multi-faceted skillset that considers everything from managing your exertion levels to food, nutrition, and hydration to your choices for cold-weather clothing, sleep, and shelter systems.
Three strategies for getting the most performance (and versatility) include:
- Two-layer insulation systems that combine synthetic and down layers for insulating clothing and sleeping bags;
- Vapor barriers in sleep, clothing, handwear, and footwear systems;
- Maximize warmth-to-weight ratios by selecting really puffy products – high loft (fill-power) down combined with ultralight shell and lining fabrics.
Disclosure
Updated November 7, 2011
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Discussion
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Companion forum thread to: Lightweight Backpacking Gear for Cold Winter Temperatures (Two-Layer Systems, Vapor Barriers, and Really Puffy Stuff)
Lightweight backpacking gear for winter temperatures: two-layer insulation systems, vapor barrier systems, and really puffy stuff.
Hi, thanks for the article. There is something I don’t understand.There is so much trouble being taken NOT to let your down sleeping bag get wet, and then the advice to dry your gloves inside the sleeping bag, and sometimes I read about boots , or boot liner inside the bag.
Doesn’t that compromise the bag?
@marjolein
Yes, putting any wet gear inside your SB (without a VBL) will simply transfer the water into the insulation. It is a ridiculous idea, even though novices still do it. You will find that experienced BPL members NEVER do it.
Well, actually, my wife & I do put out wet ski boots into the foot end of our quilts, BUT we seal them up in plastic bags first! Sealed up seriously. The idea is to keep them warm for when we put them on in the morning, but NOT to try drying them out. A lot of experienced XC tourers do this.
Let’s put it in context.
If tomorrow is wet, what is the point of trying to dry your shoes? They will just get wet again, almost immediately.
If tomorrow is dry, why worry? Your shoes will dry out on your feet fairly soon.
‘But you will die if your feet get wet’ …
Yeah, right.
River walking in the Colo Gorge. The river is the highway. Days on end.
Cheers
Excellent post Ryan. I run hotter than a lot of people so I use high breathable, non down insulation for active and down puffy once I am stopped. I tried the down quilt inside a synthetic quilt (Bozeman Mountain Works 90?) but ended up going with a vapor barrier sack inside down bag which was lighter and more manageable.
One of the reasons vapor barrier socks / mitts really win is that they don’t have material to soak in the water, so “drying out” is nearly inconsequential. +1 Roger’s shoes / boots in a sealed bag to keep warm. Yes, it’s nice when they are warm in the morning, but even more important is that they haven’t frozen in a shape which makes them challenging to put on.
more important is that they haven’t frozen in a shape
Yeah, that IS what I meant!
Frozen ski boots at -10 C: delightful stuff.
Cheers
I wonder how many people use a (not very breathable) so-called “waterproof/breathable” outer layer when it’s cold and thus trap lots of moisture in their clothing. Then perhaps add a vapor barrier inner garment to compensate.
When it’s cold I go for totally breathable everything, often wearing a sort-of-heavy 60/40 shell if I’m not worried about weight (one of the few times I’ll wear cotton, the other is when it’s very hot and I soak a cotton t-shirt in water to keep me cool).
I can’t imagine wearing a VBL when walking without getting hot and very sweaty. There is no way I would wear anything like that just for cold. It has to be both very cold and rather wet before I resort to anything waterproof.
Even in heavy rain+wind in the cold, I find sweat condensing inside my silnylon poncho which is kept very loose and flappy around me. While it has sleeves, I rarely use them. I prefer to use it as a sort of close umbrella, usually partly open down the front.
My 2c.
Cheers
Great advice @ryan. The vapor barrier shirts you link to are relatively heavy and expensive. Plus, with multiple layers in the fabrics they would add more warmth (when moving especially) than I think I could stand.
Have you ever tried a simple silnylon shirt or jacket under your insulating layers as a vapor barrier? I’m wondering if it would be a lighter and cheaper alternative to at least try the concept. Something like the Anti-Gravity Gear ultralight rain jacket would definitely be vapor-proof. But I own a MontBell Tachyon anorak that is pretty waterproof but not completely, and weighs only 2.1oz (actual). There is also the EE Copperfield windshirt that is similar.
Thoughts?
Ryan, anyway you can post a photo of your winter footwear setup? I’m trying to understand how you’re able to use the summer-weight boots with the overboots. Do you wear them in combination, or do you have the overboots in case of an emergency and need to keep your feet insulated? Thanks!
Are you going to review the Nunatac Nova (synthetic) with Nano Liner (Down) at some stage>
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@Elliot Wolin,
you are correct of course. My 6th grader wears a Pata Mission Peak running shell to bike to school most days here in northern Minnesota winter.
I don’t know about “many people” but the reason to use VBL layers is not because of using a WPB outer layer.
It is because, when it’s very cold, you add insulation to keep warm. Yet, once the temperature drops far enough, and you are wearing thick enough clothing, the dew point is inside your clothing. So even if you were wearing some magic insulating mosquito netting, you would still get condensation inside your clothing,
The fact that most traditional al high loft clothing uses calendared down proof fabrics, that are very poorly breathable doesn’t help of course.
This is were the new ‘active insulation’ come in handy, they offer a slight wind resistance, but their high air permeability allows much more moist air to move through than traditional insulated jackets. So, even if they do get damp, they dry much better.
https://andrewskurka.com/vapor-barrier-liners-theory-application/
I will also make a plug for the Pata Capilene Thermal weigh baselayers.
i have tried so many different baselayers, and these seems to do the best at moving moisture out, so for variable or continuous high output activists in cold weather, nothing else comes close.
Has anyone anything to report from the field about using silnylon jacket/pants combos as VBL clothing inside a sleeping system? Cheaper and lighter than the dedicated offerings from RBH and others.
Jon, if you read the Andrew Skurka article linked above he wears a homemade silnylon jacket and pants and goes into great detail for both on the move and sleeping.
I wear my damp socks inside down bag and they dry out over night
Wet socks – they’re still wet in the morning plus the down bag gets wet
There’s a certain capacity to dry stuff out over night, but it’s limited
Boots if it’s freezing? Make sure and open them up as much as possible, so when they freeze, you can still get your feet into them the next morning
I made a shirt and pants from Srephenson’s “fuzzy stuff”. It was sort of heavy. I found lighter base layer was just as warm over-all, just as dry. But, I didn’t do extended periods of many days at very cold temps which is the example Stephenson uses as an application where VBL works.
Boots if it’s freezing?
Put them in good plas bags and store them under the end of your quilt. They will be slightly warm in the morning, which is sheer delight.
Yes, we do that when XC ski touring.
Cheers
I’ve had such good luck with an Apex quilt over a down bag that I don’t see the need for a vapor barrier- maybe a 10+ day expedition?
My Apex quilt has a “poncho” hole so it does double duty around camp as an insulating layer allowing a lighter puffy to be used.
I’m with Jerry- slightly damp items (base layers, socks, glove liners, etc) go in the bag- worn or tucked into a waist band- they’re always dry by morning and have never had an issue with the bag losing loft (w/ a Apex quilt over top).
Wet items in the winter go in between a ccf pad and my inflatable pad, they are always warm (and unfrozen!) and even occasionally dry.
Boots on the other hand… As my bag is a three season bag I’ve sized it’s length shorter and don’t have room for boots (occasionally trail runners and they fit)
I want to put an overbuilt over my down quilt to avoid the condensation issues discussed here. But I don’t have the budget for a synthetic overquilt right now. I do have a summer weight synthetic sleeping bag that could do the trick, but it is heavier than these synthetic quilts. Money, money, money :) I also have a think fleece blanket that is lighter – I think less than a pound. Has anyone ever tried something like that as an overquilt? Did it work?
Costco have synthetic fill blankets from Eddie Bauer. Around $25 up here in Canada. Add a draw string to the foot end and you have an overquilt. They can tend to slide off so I stuck snaps to the sides of my winter pad to match a set I added along the quilt
Thank you for the suggestion Chris. We have a Costco where I live so that is an option I can explore. I’m using a hammock so if I get it over the feet in some way like you suggested I may not have to add snaps.
Any thoughts on whether a fleece blanket would work for managing the condensation? I would expect it to move the point at which condensation occurs out at least a little from my down quilt. But not sure if it will be effective enough. I’m going to a colder climate in November for a week but I won’t have any opportunities to experiment and test before that where I live.
Of course it would help keep the vapour from condensing inside the down, but whether it is weight-efficient is entirely another matter.
We use a down over-quilt covering the two of us. That way we share a lot of warmth, which helps of course.
Cheers
I’ve been burying most of my boots in somewhat uncompacted snow. They seem to be substantially warmer in the morning, probably due to snow being a better insulator than the air. Has anyone else done this?
Thank you Roger.
I’ve done that with Nalgenes (upside down) as you’re correct, the snow helps insulate. I have not done that with boots though, but I did recently purchase a longer sleeping bag and the boots will reside in the bottom (in a dry bag) :)
I’m wondering when someone should consider using a two-layer insulation system plus VB clothing, or choose one or the other? Is it an either/or, or a both-always kind of thing?
It would likely be lighter and more versatile to just bring VB suit and a very puffy down insulation, but is an overbag still an important part of the sleep system on some trips, e.g. longer trips?
Further, if using VB clothing, would it be recommended to use a sleeping bag with a highly wind resistant shell material, such as a gore windstopper or similar, given that moisture management is handled by the VB. This might allow a comfortable sleep under a tarp on a cold windy night, when a more breathable shell may allow too much heath to escape.
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