Published on May 20th, 2012 | by aleph69
The importance of layering
Layering is essential for maintaining core warmth, comfort and preventing weather related problems. It also helps if you want to go light: you can carry less and still have the ability to dress correctly for whatever is outside.
Layering allows you to build a tiny microclimate that surrounds your body and can be adapted to moisture, wind, temperature, and exertion. In it very basic form layering is divided as follow:
- Base Layer: The inner-most layer. This layer is critical because it’s in direct contact with your skin.
- Mid-Layer: Provides insulation and continues the transportation of moisture from the inner layer.
- Outer Layer: Protects you from the elements and should allow air to circulate and excess moisture to escape.
These items must be synthetic since we want them to dry fast. Cotton and other natural fibers absorb water and take longer to dry. This may lead to hypothermia even when the temperature is not so cold.
This layer is critical because it’s in direct contact with your skin. Base layers (sometimes referred as underwear) should transport moisture away from the skin and disperse it to the air or outer layers where it can evaporate. Because water is such a good heat conductor, wet clothing draws body heat away from you.
The best base layer materials are synthetics (polypropylene and polyester). These are light and strong, absorb very little water, and are quick to dry.
Base layers are available in light, medium, and heavy weights. Light layers suit aerobic activity where sweat dispersal is paramount. Midweight underwear provides moisture control and insulation for stop-and-go activities. Heavy layers are best in very cold conditions, or when you’re relatively inactive.
Here you have from left to right, a light base layer, a mid-weight one and a heavy, winter base layer.
Socks play a huge role in the base layer. Choosing the right weight and fabric is critical for keeping your feet warm or cool during extended periods. In the picture you have heavy weight alpine socks with its liners (for moisture wicking), a mid weight pair and an ultra light running pair, just to give you an example.
The mid-layer provides insulation and continues the transportation of moisture from the inner layer and into the outer layer. To slow heat loss, this layer must be capable of retaining the warmth generated by your body. Wool and synthetics are well suited to this because the structure of the fibers creates small air spaces that trap molecules of warm air.
The layer’s thickness, as with the base layer, will vary by the temperature outside. A lighter mid layer is suited for a warmer day or a cold day with activities that are demanding (like climbing or nordic skiing); while a thicker layer works better on cold days with activities that are more static. Mid-layer items can become outer layers as well.
Light-weight mid-layers such as the Patagonia R1 collection are great for high output activities in moderate cold conditions or as an outer layer on cool days.
The heavier fleeces are great for colder temps or for activities where there are longer periods of inactivity, such as stop and go missions or while stalking.
The outer layer protects you from the elements and should allow air to circulate and excess moisture to escape. For dry conditions, a breathable wind proof shell or a soft shell may be all you need. If you expect conditions to be more severe, a waterproof hard-shell rain jacket might be the one needed. A shell made of a breathable and waterproof fabric, such as H2No or Gore-Tex, will protect you from wind and rain, and allow water vapor to escape.
A warning note: Waterproof breathable is just an idea, there is not such things as waterproof breathable. Any hard shell that can keep the rain out will have a hard time letting your body heat and vapors out as well. If you are using a hard shell for a static activity this might work well, however is most active endeavors you will find yourself dump inside from the sweat build-up.
A especial kind of outer layer are the insulated garments. Like their name state, these items have a form of natural or synthetic insulation, usually within a soft shell or a waterproof breathable fabric. These are great items to throw on top of all your clothing when you stop and it’s really cold outside, it helps maintain the heat your body created while you were moving.
Let’s start with pants. Like on previous layers, the outer layers can have different thickness.
Soft shell jackets are the right answer to take outside for most conditions. Except for when it’s really poring, a good soft shell jacket will protect you from the wind, snow, ice and mild rain. Again, choose the thickness according to the weather.
The system works best when combined:
Wear a lighter mid-layer (like Patagonia’s R1) for when you are moving. Wear a soft shell on top for wind and light rain / snow protection. When you stop throw on top an insulated jacket to maintain that body heat and prevent it from escaping.
The system I usually wear when climbing or while patrolling on mountain terrain:
- A Capilene 1 long sleeve tshirt as a base layer (or Capilene 2 for winter). I might carry an extra one on the pack.
- An R1 Pullover as a mid-layer (or a slightly heavier fleece in winter).
- A softshell jacket that breathes very well and keeps light rain and snow out. If I know I will be needing more rain protection then I’ll bring a hard shell jacket too (stashed on the ruck).
- For the legs I use either nothing at all, a Capilene 1 bottoms for spring/fall or a Capilene 3 for winter, together with a pair of soft shell pants.
- On my pack I would bring an insulated jacket.
This system is light, breathes very well and it can be adapted to pretty much every occasion, even when armor needs to be wore on top. This system also keeps you warm or cool and it dries very quickly.
Stay safe, stay dry and stay warm!
I love this article Uri. Saving it for reference material. What brands have you had the most success with for your outdoor rec? When I start doing outdoor stuff, I want products that won't wear on me and they do their job well. Love your articles bro, keep 'em coming!
I'm surprised no one has mentioned my old standby Doufold, I have used them since the '70s and absolutely swear by the combination of poly next to the skin with a wool outer layer. Wicks, but you get the thermal advantage of the wool with out the prickly heat most seem to get. Even my every day socks are high content wool, summer too, they help add cushion for the serious amount of walking I do. You get accustomed to the hot feet. The notches on my ears attest to the fact that even here in the Midwest we can get some serious weather.
Uri you always have awesome posts. I backpack (avg 38lbs pack avg 13 miles/day avg 4 days an outing) and you're right on the money. You say the best base layer materials are synthetics (polypropylene and polyester) and I might add silk, if you've never tried it as a base it rules, I think Hillary wore it on Everest. But considering the combat circumstances wouldn't you need to worry about flame? The polys are just plastic and they'll melt to skin in a heat situation. What's your thoughts on that? I know wool is a great option, you can get very shear merino as a base and its more flame resistant. If anyone's on active duty check out, it could save you a nasty burn. ;)
Pretty decent read here on freezing to death...
Two companies, in different countries, on different coasts, both founded by avid ice climbers, have produced some pretty good cold weather gear. Arcteryx and Wild Things. Arcteryx was approached by the Canadian military for developing cold weather clothing; hence the subsidiary, Arcteryx LEAF. Wild Things setup Wild Things Tactical and has been producing the USMC Happy Suit for a while.
I can't speak to any product/gear working below -15'F.
Fantastic and useful article! Saving it. When I was younger I did a lot of backpacking above timberline and learned about the importance of layers and when to put on or shed parts depending on the activity so I didn't perspire at the wrong time and freeze. I was never great at it since I didn't have to perform heavy work once I reached my destination. I've wanted to try winter camping, but haven't done that yet. One of my friends spent a lot of time and hard work in the Arctic circle while he was in 5th group and he said there was a definite way to do things if you had to go from extreme hard work to being still without getting hypothermia. I read that one of the soldiers who didn't make it in Bravo Two Zero had made the mistake of having a heavy middle or inner Gortex layer. When I was young I would read about how the Inuit were experts at this having for example a heavy fur outer layer which was open and would let air in and allow evaporation while moving, hunting and heavy work, but would settle into a closed position while at rest. You people are writing about a lot of things I've always had an interest in. Perhaps sometime an article about how and when one goes about using the layers while doing different things could be done as a part two to this piece would be really great. Many thanks!
@GageReckart Thanks. Patagonia for sure, followed by Arc'teryx. I love the quality and the features that Patagonia offer. They last, the work as advertised and they do all this while using recycled materials.
@Old PH2 another great tip! Thanks! I've definitely heard about how cold places like Chicago and Wisconsin can get!
@McPosterdoor Silk rocks and I'm personally a new fan of Massif's blended wool technology for base layers. It's inherently FR and warm when wet. I have a wool sweater from them and it's the warmest piece of kit I've ever had.
@McPosterdoor So true. I wore flame resistant base layers and mid layers, but they are not as good in moving moisture and keeping that ever important layer of warm air between the base layer and the skin.
It's a trade off. If you are on a vehicle and IEDs are a real, serious and immediate threat then yeah, flame resistant is a must. If you are patrolling to a recon site or a FFP and you worry about climate control, then synthetics are the way.
Thanks for the comments and for making valid points.
@Corps Hornet Driver the Canadians do know their cold weather clothing!
@carlosferiv Well, some of it out of patagonia's website, but the softshell, level 3, level 4, etc stuff you need to get it via a gov. contract (I.E. if you are in the military...). Sorry
@carlosferiv a female supply sgt I know often uses Ranger Joe's maybe there? I worked part-time at REI once and I never saw any...I looked too.
@wannabearmyteen the one time I was in FL was on a project at Eglin. It was even in the Fall and I couldn't believe the humidity! I asked people at Ft Walton Beach how the handled doing chores in the Summer and they told me that you get the heavy yard work done before 10am and then go inside under the air conditioning! The local food and seafood was amazing and although it was only about two weeks, I nearly got the accent stuck. (has to do with where I grew up. Country and drawls can hit me and not go away)
@Logan F Crooks Well, PCU is essentially this, layering.
@ArcticWarrior That's the stuff I'm talkin' about! (again) I loved reading about that growing up and am totally amazed at what the and for that matter that group which guarded the Aleutians!
Go stuff AW!
Having spent time fair amount of time in the Brooks and a few other locations, I learned a minor CONUS injury can quickly become life threatening AK.
And I never go anywhere in AK with gear suitable for spending a unexpected very cold night out-of-doors.
I have not had the pleasure of experiencing so cold my burner wouldn't light off.
Spent some time on a reindeer ranch in the Arctic Circle. Sleeping under and against fur was a new experience, still not forgotten some 20 years later!
@ArcticWarrior @wannabearmyteen Wow! Yep, I can get seriously air or seasick depending on the ride. Diesel or exhaust fumes and a wall of hot humid air blurgh! Because I have a lot of veins near the surface of my skin and skin color, when I get sick, I really do turn green. People have stared and told me that. My first real experience of a medium serious case of shock was when I got into a minor motorcycle accident (I used to ride a CM400), on a turn at a sensible speed because of a slick concrete surface with fresh dry silt, my bike went down with my right leg trapped and dragged me a bit of a way. I couldn't get my leg free and when I tried to sit up (all this viewed from inside my helmet) I got nauseated and the next thing I remember like no time had passed was looking up at a circle of EMTs!
@ArcticWarrior @wannabearmyteen it feels funny hitting 'like' where someone gets hurt, but it refers to the content. I couldn't believe the terrain and foliage of the firing ranges I was on. It was Fall and the humidity was bad for me. I've been told by my friend that Rangers helping each other like that and motivating their buddies is absolutely part of what comes out of the training. (I guess like the buddies in BUD/S I guess). I've had that experience twice. One time I was out of shape leaving a bowhunting trip where we had to hike uphill for about four miles (far for someone as out of shape as I was at that point). I let myself get dehydrated, started floating and then was jerked out of that by what seemed like every muscle in my body knotting. I must have looked like Curly when I flipped and landed on the trail hard. Odd thing about some hikers. A few passed me in a nearly fetal position because of the knots and they said "Gee you must be tired" and kept going...niiice.
@ArcticWarrior ...and nerdy enough to extract the tracks from a video, convert to mp3 and then upload to your domain :P
@ArcticWarrior that movie and the idea of digging up ancient stuff in the Arctic or Antarctic still gives me the chills a little!
@ArcticWarrior Dead on! John W. Campbell wrote it (Who Goes There) and this link is a great description (he was the editor of Analog magazine for many years). Just like Matheson's book "I Am Legend" inspired so many later movies and possibly be one of the main causes of the Zombie genre, I absolutely believe that the way in which the director created suspense and even the environment heavily influenced Ridley Scott in Alien. Dark and maze like tunnels and the use of the Geiger Counters to show the thing approaching and sometimes just passing by was genius and there's no doubt in my mind that it's where the motion detectors in Alien/Aliens came from. I first saw it on TV when I was about in 2nd grade and that movie scared me into the next century! http://en.wikipedia.org/wiki/Who_Goes_There%3F
this page isn't finished - just showing some of my early reads and movies which influenced my interests at least a little:
@ArcticWarrior gee - this reminds me of the movies "The Thing" (both of them), "Insomnia" (2002), and "30 Days of Night" wow. I've had one friend who worked at Thule and he told me about the rope between buildings so you wouldn't get lost during whiteout and a slightly eccentric guy I worked with who loved working in Antarctica for the Nat'l Geophysical Year that he went twice in a row and was trying to get back again! Whew!
@ArcticWarrior Dear gosh! Supercooled water, wind, sloppy ocean etc etc it's incomprehensible even knowing about dry-suits etc (guess what? I was LA Co and NAUI certified at one time too <grin>). The closest I've ever experienced anything like that taught me to avoid cold water at all costs. One time backpacking in college above timberline (~12,000 ft) - I had the brilliant idea (pretty much like jumping off a friend's roof with an umbrella in 6th grade) of jumping in a stream next to and fed directly by a glacier (not even sub-freezing sea water). I jumped in - and I honestly think that I teleported instantly back to the shore - all I remember is that feeling of all those knives sticking in me!
@ArcticWarrior off topic sort of but having grown up in SoCal, you know how we are...68deg and you're putting on sweaters :) The coldest I've spent outdoors was a bowhunting trip but that was only 20deg. I do know how much healing from frostbite hurts, but it had nothing to do with WX. As a student, I worked a lot with cryogenics (that's how you do fractional distillations of Boron chemistry, a glass vacuum line with 'U' shaped tubes and you put Dewars under each with different frozen concoctions and trap everything before it gets to the mercury vapor pump with LN2. LN2 is easy to work with. Everything was not too unsafe, but liquid Freon with Freon ice is murder. You have to keep breaking the ice that forms on the top of the Dewar flask around the vacuum line w/o breaking anything. I'd use a wood dowel. One day a chunk of Freon ice flies out and lands on my arm. Nothing you can do, instant frostbite. Hurt like the Dickens and it might have dissolved into my skin so I had to get a little tumor like thing removed later. owww. When I would have a lab explosion, I was the one who had to clean up something like a liter of mercury off the benches and floor - which may explain a few things <boing cuckoo> oops way off subject.
@ArcticWarrior some stories I've heard about operating in those conditions came from a friend I had about 15 yrs ago, an RVN CSAR guy who later worked training soldiers in survival in the arctic. The others I heard were a few from my 5th group friend while he was stationed up there.
@ArcticWarrior haha - I totally understand that. I'm going to find a good book about the ALCAN, there was a documentary about them on either Discovery or the Military Channel - and yes. It is really sad when stories like those aren't written until it's too late.
@ArcticWarrior @Corps Hornet Driver I read his old book and it was always one of my favorites!!!! Taught me I never want to get carbon monoxide poisoning for sure! That is really great about having a small business who knows their stuff making that! I knew a guy who used to go Moose hunting up in Canada all the time and having to cut through BC thick stuff for miles to pack back a ton of dressed out moose. He relied on a primitive home made pack frame (wood staples and canvas webbing with a 1x1 or slightly larger on the bottom like the "L" on an Alice pack). I tried it and it was amazing for carrying heavy loads. By the time I found and contacted the family in Canada, he had passed away and they had parts but not the knowledge of putting it together - what a shame!
I will absolutely check out those books. A funny. A few weeks ago I happened to talk to a lady while window shopping in our small town. She's a CAP pilot and absolutely swore that I was Aleut. I told her I couldn't be, I couldn't survive that cold! :)
@ArcticWarrior if I ever have the money, I may have thought of a new use for my Barrett :)
@ArcticWarrior @jrexilius Great!!! Wow! I am seriously impressed (even that you can live there comfortably). "I alwayws pestered the old retired Eskimo Scout guys for tips." That is EXACTLY the kind of thing I'd do. I read that real Wolf fur around the hood is also one of the few which holds heat and doesn't collect frost from your breath.