Marina Pitofsky begins her USA Today article by quoting a gentleman who works in Antarctica: “You need lots and lots of layers.”
In a word, “No.”
No, I do not live in Antarctica. I do live in Colorado, however, and have spent my share of cold weather camping trips, including times below -20 deg F. I also attended a military survival school and have thoroughly researched heat and cold management in housing construction (same principles).
In actuality, you need four things:
- Thermal mass
Some materials provide multiple benefits.
Insulation impedes or prevents thermal conduction. It is simply dead air space, or better yet, vacuum, the perfect insulator. Vacuum requires no baffle, but air conducts heat, so air does require a baffle, which minimizes the movement of thermally conductive air in the dead air space. In homes, we use fiberglass. For clothing, we use minimally conductive fabrics with high loft and low thermal mass. Humans used animal furs, first, while still attached to the hide. During the textile revolution, they began weaving animal fur, primarily wool, into their clothing to provide that loft. Mixing soft furs, such as angora, in with the wool provided a much more comfortable feel while adding both loft and baffling. Polar fleece, which is made from 100% polyester fiber, is widely used, relatively inexpensive, and quite effective.
Unfortunately, even a mild breeze can push right through fleece, so serious winter jackets include some kind of shell as a barrier against wind and rain. The earliest barriers were animal skins, often known as an “oil slicker,” and treated with oils and oily waxes in order to render them waterproof. They didn’t breath, but they were loose enough, usually draped as a poncho or robe, that air came up around the bottom to minimize moisture build-up. For winter use, one would use real sheepskin fleece, with the fleece turned inside out so the outer layer would repel the water while the inner fleece layer was kept warm and dry against one’s inner clothes. This approach also allowed ventilation through the fleece itself, again, to minimize moisture. Modern barriers have evolved from rubber-impregnated cloth to tightly-woven nylon, synthetic barriers like Gore-Tex, and a variety of modern woven, water-repellent fabrics with excellent ventilation while shedding snow, rolling away the rain, and stopping even the fiercest wind.
While early garments were non-breathing skirts and robes, which provided bottom-up ventilation while sealing in at least some of the warmth, modern garments breath through the fabrics themselves while sealing in the heat. Thus, seals are used to prevent that heat from escaping through holes for the face, neck, hands, waist, and feet. Before the advent of stretchy materials, zippers, and Velcro, older seals often involved laces. A simple design involved a “butterfly tie.” The key here, however, is to prevent warm air from escaping while also preventing cold air and the elements from entering. Seals shouldn’t be tight, but they do need to be somewhat snug.
Vacuum-sealed thermos bottles also employ reflection. This layer of mirroring on the glass, or polished aluminum on the vacuum side, reflects radiated heat back to its source. The modern housing industry uses reflection throughout construction, including an aluminized mylar layer on insulation both in the walls as well as the ceiling. It’s usually used in climates with significant radiative elements, such as in Las Vegas and Phoenix, as well as Minnesota and North Dakota. In hot climates, you’ll find it facing the exterior, to prevent heat reaching the stucco from being radiated into the insulating layer. In cold climates, you’ll find it facing the interior, to reflect interior heat from leaving the living space. This is important, as even in hot climates, you want the interior structure to be able to radiate inside heat into the walls while minimizing external heat from doing the same. Clothing manufacturers sought to do the same using flat, aluminized threads in various garments, but that was more of a gimmick than anything practical. In fact, polar fleece (100% polyester fiber) is itself quite good at reflecting heat. If you’ve pulled a fleece blank over you and felt its instant warmth, that’s actually two things at work, primarily reflection, but also insulation. Not only is it reflecting your own heat back to you, but when it touches your skin, it’s barely conducting any heat away from you. Compare that to a heavy cotton quilt that takes a long time to warm up when you duck beneath the covers in a cold room at night!
Thermal mass is used to moderate temperature swings. It’s usually, but not always synonymous with actual mass, as material like rock tends to have a high thermal mass whereas the thermal mass of polar fleece is very low. In housing, thermal mass is provided by sheetrock (wallboard), brick, stone, and stucco. For winter garments, thermal mass is generally disregarded, except as an element of comfort. Thus, if you’re in a cool, dry, non-exerting environment, a thick cotton shirt beneath a layer of polar fleece provides a good deal of comfort. But if you’re exerting yourself or in a humid environment, you’ll want a material next to your skin that abhors water.
Time for some direct and practical application!
This knowledge and experience does not translate into “lots of layers.” In fact, there were a number of incorrect, misleading, and frankly, just bad advice given in the article from Antarctica, including:
“Lots and lots of layers.” Erm… No! You need some layers in cold weather, yes, and by “some” I mean “two to five.” If I’m walking in 0 deg F weather from my car to the grocery store, I’ll be wearing a cotton t-shirt and a polar fleece jacket. Two layers is really all I need. If there’s wind, rain, or snow, I’ll add a shell. If the temp drops lower, I’ll be wearing thermals next to my skin, not cotton, so that still just three layers. Climbing a 14er, I carry four layers: Thin thermals (Duofold), thin fleece sweater, a medium fleece jacket, and a shell. In the coldest of weather (20 below), I’ve worn a thick fleece jacket, as well, and was super toasty in five layers. To me, that’s a lot of layers! But it’s not “lots and lots of layers.” Even during Antarctic operations, they don’t wear “lots and lots of layers.” They wear snowsuits, which are one really thick, somewhat breathable, tough-fabric body-suit with openings at the wrists, ankles, and face. It’s tough enough you could slide on rocks without ripping it. Good ones have an inner zipper towards one side of the middle and an outer zipper towards the other side of the middle. The overlap keeps the cold out far better than a single zipper. Even so, you’re still looking at just three or four layers!
“Insulation layers close to your core are incredibly important because that helps you retain heat.” This implies that wearing polar fleece directly on your skin is good. That’s not the case. In reality, insulation between you and the outside is what retains heat, but it doesn’t have to be “close to your core” in order to do it’s job. You need at least some thermal mass for comfort, and a layer that can moderate humidity, as well. In dry climates, with minimal exertion, cotton is actually quite good, provided you have enough insulation on top of that to keep the cotton close to body temperature.
“One of the biggest challenges is being able to know your limits and accept your limits.” I like his suggestions, but I see this as more of being realistic, if not pessimistic, than being optimistic. In the military, I learned to “hope for the best, but plan for the worst.” I spent a lot of time making plans that were never needed. The few times they were needed, however, they saved my life. Thus, instead of “accepting your limits,” I see this as an opportunity for risk management. I carry a small bag with me in the car throughout winter, but that bag contains everything I need to mitigate danger, particularly in case of an accident: A quart of water, a two-days supply of medication, thermals, gloves, mittens, a hat, thin fleece uppers and lowers, and shells. It’s not intended to replace what I’m wearing. It’s intended to extend my ability to survive in case I wind up having to change a tire during a 20 below blizzard. Foster says, “It’s not worth getting severe frostbite.” I say, “wear the right gear and you won’t get severe frostbite.”
“Watch out for each other.” That’s so true. However, help others watch out for you by giving them a “float plan.” In aviation, we call it a flight plan. If you’re travelling, it’s a travel plan. It includes all the information rescue personal may need to find you: Your name and phone number, a detailed time-based itinerary, and the make, model, color and license plate of your vehicle. When you leave, let someone know. If you’re delayed, make that call. When you’ve arrived at each leg, pick up the phone. If you’re travelling through seriously severe weather, schedule periodic check-in calls. Plan for what your point of contact will do if you’re out of contact. For example, if you’ve scheduled yourself to check in while passing or stopping in three cities, and those cities are two hours apart, then obviously, somethings probably not going as planned if three hours elapses. Have a plan.
In all things, err on the side of caution, if you’re cold then GET OUT of the cold, plan ahead, carry more gear than you think you’ll need to include food and water, even for a cross-town trip, and maintain communications.