By Michael Lanza
If hiking, backpacking, and climbing from spring through fall teaches us the fundamentals of layering our clothing for comfort in variable weather, the backcountry in winter confers a graduate degree in layering. In mild temperatures, getting wet with perspiration or precipitation merely risks discomfort. In freezing temps, it can quickly lead to hypothermia and actually become life-threatening.
This article offers expert advice on how to choose a specific, personalized layering system for different exertion levels and body types in backcountry in winter. Drawn from my three decades of Nordic and backcountry skiing, snowshoeing, climbing, camping, and trail running in winter—many of those years as the Northwest Editor and lead gear reviewer for Backpacker magazine and running this blog—these tips go beyond the usual layering advice to help you stay comfortable and safe by customizing clothing systems according to activity and body type.
See my “12 Pro Tips For Staying Warm Outdoors in Winter” for advice on how to manage your activity level in combination with your layering system to minimize sweating.
A layering system is simply the clothing layers you wear outdoors, and we all understand that dressing in layers allows us to make adjustments—adding and removing layers—as needed for changing conditions. My “10 Tips For a Smarter Layering System” apply primarily to three-season conditions. But temperatures near and below freezing compound the challenge of dressing comfortably during exertion, when our bodies sweat, because damp clothing conducts heat from your body, and cold air rapidly accelerates that cooling effect—potentially to a dangerous degree.
Choosing a Layering System
Three variables dictate the layers you need:
• The ambient conditions you expect to encounter—temperature range, wind, and precipitation—as well as how terrain and vegetation cover affect your exposure to the weather (i.e., you’re more protected from wind and weather in the forest than above treeline).
• Your level of exertion, whether moderate (downhill or backcountry skiing or riding, ski touring, or snowshoeing) or highly aerobic (fast Nordic skiing, trail running).
• Your body type and metabolism, or more simply, how easily you get cold.
Think of those variables on a sliding scale. As we all understand, you need warmer layers as temperatures and exertion level drop. But your choice of specific garments will also depend on your body and activity, and some apparel can cross over between the two types of layering systems.
See “The Best Gloves For Winter” for both high-exertion and moderate-exertion activities.
Base Layers for Winter
Whatever your exertion level, you want next-to-skin tops and bottoms that do two things:
1. Wick moisture off your skin quickly.
2. Provide at least the minimum amount of warmth you need for the conditions and your body.
In winter, those two traits become especially important. A top that’s too light reduces your layering system’s versatility by forcing you to rely only on your insulation layer for warmth—and insulation that’s warm enough for the coldest temps you face, as it should be, may be too much at other times.
See the best base layers for being active outdoors.
On the other hand, you also don’t want your base layer top to make you overheat, which can happen in the warmest circumstances you might encounter—such as skiing or snowshoeing uphill in sunshine, calm air, and temps around or above freezing. It’s also possible to overheat when moving uphill in temps just below freezing and snow falling hard enough that it requires you to wear a shell jacket. In that situation, an insulation layer may be too warm, so you need a base layer under that shell that provides adequate warmth.
You can also combine two base layers, a lightweight one and a midweight, giving you another possible layering adjustment to deal with fluctuating temps. (Or you can moderate your pace, which is another of my “12 Pro Tips For Staying Warm Outdoors in Winter.”) But peeling off and putting on base layers is less convenient in winter than in summer—especially in falling snow or when you’re wearing an avalanche beacon. Better to have one base layer that does the job.
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Pants for the Backcountry in Winter
We swap out top layers in winter, but not our bottoms. Depending, of course, on the activity and conditions, we generally wear one or two bottom layers and do not change them while outside. Consequently, our pants or bottoms must be chosen specifically for the activity and conditions.
Here’s what to look for:
• For trail running, I often wear running shorts over compression shorts or three-quarter-length tights (which reach to the top of the calves and cover the knees) with compression calf sleeves or socks; or lightweight, highly breathable, fast-wicking tights.
• When Nordic skiing, I favor lightweight soft-shell pants that breathe well, block some wind (for skiing downhill), shed snow, and offer a bit more warmth than tights. This type of pant crosses over well to three-season hiking and climbing in the mountains, too.
• For backcountry skiing or snowshoeing, I want more substantial pants that still breathe well, but are designed to keep snow out of ski boots (with a feature like an internal gaiter) and deliver a bit more warmth and weather protection.
Which puffy should you buy? See “The 10 Best Down Jackets” and
“How You Can Tell How Warm a Down Jacket Is.”
Two Types of Layering Systems for Winter
When it comes to a shell and insulation, most people will employ one of two different types of layering systems in temperatures from just above to well below freezing:
1. Layering for moderate-exertion activities of anywhere from an hour to all day, or even multiple days if you’re staying in a backcountry cabin or yurt or winter camping. That demands a versatile system, with three or more layers, that allows adjustments dictated by changing conditions.
2. Layering for high-exertion activities, which are usually of shorter duration—a few hours or less—and often may not involve making adjustments, such as when Nordic skiing or trail running.
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The Best Moderate-Exertion Layering System
If your primary winter activities are backcountry skiing or ski touring, snowshoeing, or hiking, you need a layering system with great versatility, which usually means three types of layers: base, middle or insulating layer, and shell.
This could consist of just three pieces, and at times, you might only wear one layer over your base top: insulation for warmth when it’s not precipitating, or a shell to fend off falling snow when you’re working hard enough to stay warm without insulation. You might, of course, wear two base layers (one lightweight, one warmer) or even a combined vest and insulating jacket as “middle” layers, with or without a shell.
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Insulation The classic middle layer is critical because it provides most of your layering system’s warmth. It should also breathe well, because your outer/shell layer will already be the least-breathable piece of the system; more than one layer with limited breathability can quickly start feeling clammy. The good news is that there’s an ever-expanding array of options in insulating layers that breathe well, some of which also cut some wind. Your middle layer will many times pull double duty as an outer layer when you don’t need a shell.
Shell In winter temps from above freezing down into single digits, I want a shell jacket with superior breathability, because I can overheat skiing uphill in the backcountry, but also built to repel hours of falling snow and block most wind, with an adjustable, brimmed hood that keeps wind and precipitation off my face. While not many years ago, these fully technical shell jackets fell on either side of a fine line between soft shell (highly breathable but not fully waterproof) and hard shell (fully waterproof but not quite as breathable), today you’ll find shells that blur that distinction, with the supple feel and breathability of a traditional soft shell while delivering fully waterproof performance.
Lastly, for multi-hour or multi-day adventures deep in the backcountry in winter, far from the nearest road, you need a warm puffy jacket both to prevent you from rapidly cooling off during short rests, and in case of an emergency. The best are stuffed with enough insulation to keep you warm when stationary in temps well below freezing; have a hood that closes snugly around your noggin (and in some cases, over a helmet); and have properties that help them repel moisture and falling snow, like a DWR (durable water-resistant treatment) on the shell, and synthetic or hydrophobic (water-resistant) down insulation.
The Best High-Exertion Layering System
If your winter sport of choice involves sweating and breathing hard, like running and Nordic skiing or even power hiking, fabric breathability becomes the top priority in your outer layer—you need to dump as much of the moisture your body is producing as possible, to avoid getting too wet. Your jacket should also have enough water resistance to not soak through in light rain or snow, but a fully waterproof-breathable jacket is typically overkill, because it’s not nearly as breathable as a water-resistant shell and usually heavier. Besides, in temps below freezing, you don’t need a waterproof jacket; a water-resistant shell can shed falling snow.
This layering system usually consists simply of an adequately warm, often midweight base layer and a lightweight, very breathable jacket. Occasionally, I’ll wear a lightweight base layer under a midweight, when I need a little extra warmth, because for these activities, I’m not wearing an avalanche beacon or likely to make layering adjustments.
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A Tip About Hoods
Most of the time, I like having any kind of hood on a jacket—and I definitely want an adjustable, full-coverage hood on a shell for multi-hour activities like skiing or snowshoeing. But understand the pros and cons to having a hooded middle layer.
Hoods come in basically two styles:
1. Very close-fitting, non-adjustable, usually elasticized hoods intended to just provide some added warmth and good breathability, but minimal wind and weather protection. They are usually found on insulating layers or lightweight jackets that are worn alone, and designed to fit under a ski or climbing helmet.
2. Adjustable, “fully technical” hoods on a shell that deliver complete weather protection and fit over a helmet or any hat.
While there are advantages to having an insulating layer with a close-fitting hood for warmth (type 1 above) as well as a fully technical hood on your shell (type 2), if your system has more than one hood, make sure they fit well together when on and off your head. For the most part, insulated jackets have either a close-fitting hood or none; but some insulated hoods are bulky and don’t fit compatibly with all shell hoods. Two high-volume hoods are too many. Test them together.