Sunday, December 5, 2010

How to stay warm in -40 C

Earlier this week I found an interesting infographic showing what clothing Lars Monsen and Hardald Tunheim recommends to stay warm and without frostbite at -40 celsius (-40 F). I don't know anything about Harald Tunheim, but Lars Monsen is probably the most well known outdoors person in Norway. If I bring my stove on a trip people will often comment "that is so Lars Monsen". He's super experienced after being an outdoors person all his life, and after completing several challenging expeditions, like crossing Canada with dogsled. He's made several TV shows and written books about his expeditons and about gear and techniques.

Here's the infographic with a translation to english below:

How to dress for extreme cold
These are some clothing tips from harald Thunheim and Lars Monsen, both dog sled drivers. They have both experienced extreme cold and know how to dress to avoid frostbite.

Wool beanie with opening for face (my comment: balaclava?).
(Harald Thunheim prefers a fur cap with sides that can be connected below the chin with velcro. He also uses goggles and a face mask if there is a lot wind).


The neck is covered with wool.

Upper body
Wool sweater with neck, vest or down jacket.
Two wool shirts, short and long sleeve.

Outer layer

Windproof jacket made out of a strong fabric, and with a solid hood. Should be long so that it covers the buttocks.

Outer layer: Sealskin mitts that covers much of the lower arm (windproof).
Inner layer: Wool mitts.


Two wool long underwear bottoms.
Outdoor pant or fleece pant, preferably with reinforced knees.
Thick, insulated field trousers.

Thick wool socks, two pairs.
Shoes made from pure wool.
Use shoes that are a couple of sizes too large. Insert thicker and better isolated insoles as the cold comes from below.

Don't shower every day
Lars Monsen thinks that a layer of dirt protects against the cold, so don't shower as often.

This clothing setup is of course mostly geared towards dog sled drivers and people staying mostly stationary in camp, as well as people who don't like deodorant. Any heavy physical activity would probably make a person hot and sweaty, needing to shed some layers, but then again : -40 C is pretty cold.

Staying comfortable and dry when moving in -7 C
I went for a walk today in the forest close to where I live and I learned something, I always do when I am out.  The temperature was -7 celsius (20F) with some light snow falling and no wind.

When I left I was wearing synthetic socks with wool socks on the outside, hikings boots, high gaiters, Woolpower long underwear bottoms, Lundhags pants (cotton/poly blend), synthetic baselayer from Stormberg, Patagonia R1 hoody, Polar Buff, beanie, Marmot Driclime windshirt, fleece gloves and MLD rain mitts. I started out a little chilly and then I felt my back getting warm, so I removed the windshirt. After a while my ears got chilled so I put on the hood/balaclava of my R1. This shedding of layers and putting them on again continued the whole trip, with the goal being to not get sweaty.

Now you might say that getting sweaty isn't a big deal, and in summer it isn't, well except for potentially scaring friends and wildlife with your body odor, but it is in winter. Imagine you're working hard, walking on snow with your snowshoes on. You've felt your baselayer getting wet from perspiration, but you've not stopped to take care of it because you're a lazy or you don't want to make your friends wait. After a while you decide to stop to eat something and snap some photos, but you're stilling wearing what you wore while moving, not adding any insulation. Now you're not moving anymore so your body isn't producing warmth like before. Since you're still somewhat warm you're still sweating some and the sweat is evaporating from your skin, taking warmth with it. After a while it stops evaporating, but your baselayer is still wet and water transports heat 25 times more efficiently than air, hard facts that you definitely don't like in that situation. So, you really want to be observant and shed layers when needed to reduce sweating, and you want to put on some insulation as soon as you stop. I knew all of this beforehand of course, but I haven't been this focused on it before, mostly hiking in warmer conditions. In winter it is essential to be mindful of this.


  1. Nice summary of your winter gear Thomas. I'm walking around in similar conditions (-10 now), but I tend to get a little colder it seems. I'm not usually so bothered about my legs, but on my top I have a base layer, First Ascent Hangfire hoody (a little heavier than the R1 I think), and often my Halti down jacket. Often I get too warm in that and have to open it for venting. I'll try going out with the Driclime, but I feel I might be too cold. I really need to sort out some decent layered gloves though. Hate having cold fingers.

    As for -40C, it seems Lars is a big fan of wool! When it gets really cold I slip on a fleece and a warmer base layer.

  2. What I was wearing isn't really my typical setup. I would definitely add my Thermawrap Parka or a down jacket, as well as more hand and head insulation. I just wanted to test that setup as I knew I would be back home within an hour ;)

    That First Ascent Hangfire hoody looks interesting.

  3. Yes. I just tested your setup, and it's not bad if you keep moving at a reasonable pace.

    The Hangfire is a nice top, but looking at it closer, I'd be really interested to compare it to an R1. In some places, the lining appears to be nothing more than padded mesh, with patches of micro-fleece here and there. I've noticed that sometimes it feels a little cold, which backs that up. I should do a proper review, and maybe I will...

  4. Thomas, what do you think of VBL - Vapour Barrier Layers?

  5. Maz: I have no experience with VBLs, but have planned to experiment with it on my next winter camping trip, that is if its cold enough. Have you tried it?

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  7. Merino wool prevents bad odours. Juxtaposing that to Lars Monsen's advice to shower less I assume he wears merino wool garments. ;-)

    During my relatively few winter camping trips a merino wool base layer and long johns (Woolpower 200g/m2) have kept me warm in -13C. On top I wore a Woolpower full zip jacket (400g/m2) which I just love.

  8. I suspect merino is far too namby-pamby for Lars. Just look at him! He probably wears the whole sheep.

  9. -40 C is terribly cold. Standing around not doing anything in temperatures like that makes it very difficult to stay warm. Even on a dog sled you are actually doing some work.

    Even apart from getting your base layer soaked, sweating is always poor energy economy. In order to keep the body temperature around 37C the body looses energy (through evarporating the moisture on the skin) and, of course, water. Both the energy (coming from food) and water (coming from drink) certainly could be put to better uses when the solution is so simple; take of some clothes.
    Rule of thumb; if your are sweating and not already naked you wear to much clothing ;-)

  10. Thomas: no I haven't, but I read a very useful analysis on Andrew Skurka's website which you should check out and which has given me pause for thought -

    Mark: I once saw a documentary about some hunters in the frozen north of Scandinavia who actually ate three times as much food each day in the run up to a long trip so they'd get a layer of fat to insulate them. That's hardcore.

    Jörgen and Thomas: thanks, very useful discussion.

  11. Eat more. Shower less. I like the sound of this winter backpacking! ;-)

    I was out in very similar conditions on the weekend as you Thomas. I wore a Power Dry hoody (the MEC version of the R1) and my Rab Alpine Pull-on which is Pertex Equilibrium. I stayed just the cool side of warm but more importantly I stayed DRY. This has been my quest this winter. I know I can stay warm but I somehow always used to end up damp. No problem on a day hike or even an overnighter (we're all pretty resilient at putting up with a bit of discomfort for short periods) but with longer trips on the wintery horizon it's keeping dry that is the key. No merino for me at this time of year. Synthetics, for me, wick better and dry faster.

  12. Joe: that's why I went for the Páramo Mountain Pull-On as a base layer for really cold weather - it dries so quickly but is thick and warm as well.

  13. I sweat a lot when exercising and find the "move so slow that you don't sweat" thing to be impossible... To cope I will skip a shell as long as the wind isn't blowing and just use base layers and fleece midlayer or if it's windy try just merino baselayers (or if it's cold syntethics wih merino over it) and a shell. Top off with a hat like the lowe mountain cap and good gloves I'm fine as long as I'm moving.
    By the way the Norwegian broadcaster NRK has torrents of one of Lars Monsens tv series This is a year round trip around nothern Norway, Sweden and Finland... I think there is english subtitles available as well...

  14. "Now you might say that getting sweaty isn't a big deal..."

    No. No, I would not say that. I would never say that when referring to winter conditions.

  15. Jörgen: definitely need to be moving at -40C :)

    Mark: thanks for the link to info on VBLs, I will check it out

    Joe: thats my quest too, the quest to stay dry :). Had planned to use thin merino though, but will consider using more synthetics

    Gaute: can you send me an e-mail at ? I need to ask you about something

    Samh: yes, winter conditions are to be respected for sure!

  16. I think in winter you need to start off wearing less than you think you need otherwise you'll need to stop almost immediately to remove layers.

    I was lazy when I was out on Saturday and didn't bother to remove my softshell even though I was really too warm, when I stopped I needed to add a light down jacket. Out again on Monday it was colder but when I needed to put my shell jacket on I first removed my softshell. Although I was expending more effort than on the previous day I didn't sweat and only on my last stop late in the day I needed to add a layer but only the softshell rather than the down jacket.


  17. "I once saw a documentary about some hunters in the frozen north of Scandinavia who actually ate three times as much food each day in the run up to a long trip so they'd get a layer of fat to insulate them. That's hardcore."

    The body fat itself doesn't work as an insulation or keep you warm but to stay warm you need energy to keep metabolism running. And in certain winter conditions and on certain trips one simply can not eat as much as he consumes so the rest of the energy has to be taken from the body.

    For example in polar travelling with heavy sledges (for example because of food and fuel for 120 days and gear to stay warm in -40C temps) one can consume over 8000kcal per day and will likely average over 6000kcal per day. This causes the body to burn itself quite fast and to spare the body and some muscle to make the trip, getting extra mass before the trip is a good idea, even compulsory. And hard core as hell!

    For example some of the Finnish Airborne rangers who skied to North Pole in 2006 boosted their diet with a daily glas of olive oil. On the trip they ate about 6000kcal/day and lost average around 10kg of bodyweight and two of them 16-17kg!

    And btw, the guys on the expedition stayed warm in -40C temps with merino underwear, fleece layer (or two) and Gore Proshell. Working hard keeps one warm. For pauses they had down clothing (jackets and pants) made for 8000 meter peak mountaneering. And the tents were heated with white gas stoves while not in the sleeping bag. Watrm tent is great in the heart of winter. =)

  18. Mac E: definitely a good idea to start out wearing less than you think you need, to the point of being a bit chilled, but it is hard when its cold out :)

    Lightening up: thanks for that comprehensive comment :). Very interesting to read about the airborne rangers. A glass of olive oil sounds pretty hardcore.