An Intro to The Layering System
The key to comfort and ultimately the success and safety of any backcountry outing comes down to having the right clothing to keep you protected from the elements as well as keep your body at a comfortable temperature. The human body has a narrow temperature range that it needs to stay within to work at its optimum level. If it gets too cold or too hot, its efficiency decreases and ultimately hypothermia or over heating and sweating can become a problem.
Having the correct clothing means that all of the individual components have the ability to work with one another in some sort of a system. This system is based on the layering or stripping of clothing dependent on the weather, temperature, amount of exertion, and personal physiology. The goal of a layering system is to have enough clothing to stay comfortable in the worst conditions that you might encounter on trip, without having extra, or redundant items that may not get used, or will simply weigh your pack down.
In this article I will briefly cover a 5-layer system that can be used year round with minimal additions or subtractions to custom taylor for warmer or colder weather.
The baselayer is the heart of the layering system. This layer will be used year-round. The baselayer or lightweight layer is worn snugly next to the skin and is responsible for wicking excess moisture away from your skin. By transferring moisture away from your skin evaporative cooling on the skin is minimized thus allowing you to stay warmer in cool conditions. Baselayers will be made from merino wool or synthetic fabrics. Cotton is not an option for a baselayer as it does not dry readily and will increase evaporative cooling at the skin level when wet. Merino wool tends to insulate better than synthetic blends, but dries slower, and is less durable over time. Synthetic fabrics will dry more quickly and are more durable than wool, but tend to hold smells more. Baselayers must be protected from the elements as they do not shed rain or snow and do not block against the wind. On hot days, light colors will reflect more sun minimizing solar absorption, thus feeling cooler. Darker colors will absorb more sun feeling warmer on cooler days.
Mid-weight / 2nd Layer Top
The 2nd layer or mid-weight layer is responsible for providing additional warmth, but not so much that you will overheat while being active. This layer must also be breathable. Avoid fleece with laminates to stop the wind. These limit breathability and will cause overheating when your activity level is higher. Generally a light fleece will work great as a 2nd layer. A fleece alone will not block wind, but you can add an ultra-light wind shirt, with no lining on top of the fleece if you need to keep a breeze at bay. Fleece that has a tighter woven face fabric will be more wind resistant and durable that a fleece with a brushed exterior. Fleece with a “waffle patterned” interior will be warmer for it’s weight, as more air can be trapped providing better insulation with less material.
The softshell layer is probably the most confusing layer of the entire layering system. Softshells are wind and water resistant (not waterproof) as well as highly breathable. For climbers and mountaineers, softshells are the action layer when weather conditions are good to fair. Softshell pants and jackets come in many different thicknesses and weights. If you are primarily going to be backcountry skiing in the winter, a thicker softshell will provide more warmth and weather protection. If summer-time mountaineering and alpine climbing is more your flavor, a thinner softshell will keep you from overheating, but still will provide adequate protection from wind and light precipitation. Materials in softshell can be a stretch-woven material, or a light windproof outer layer with a hung wicking inner liner. Most thicker, warmer softshells will have a light brushed layer on the interior while thinner softshells generally do not.
Waterproof Shell Jacket / Pant
The waterproof shell layer is the layer that you hope stays in your pack and will not be needed. If the weather warrants using this layer, you want to make sure that if fits over the other layers comfortably. Waterproof, breathable shells come in different weights and thicknesses. Thicker shells (3-ply) will be more durable, but generally are heavier than thinner, lighter weight (2-ply) shells. If your activity requires you to wear a shell layer a lot, or while climbing technical terrain in adverse conditions, a thicker shell will be more durable and will serve you well. If there is a chance that you will not even need to put on a shell for your trip, are climbing less technical terrain, a lighter shell would be the ideal choice as it will be less weight in your pack if unused.
The insulated jacket is the part of the layering system that when you put it on, you will instantly feel warm and cozy. The best type of fill for an insulated jacket will vary depending on where you are climbing, and what type of weather conditions you may encounter. If cold (below freezing) or dry conditions are what you expect, then goose, or duck down fill will be ideal. Down provides the best warmth to weight ratio, but does not insulate well if it becomes damp. For cool (freezing and above) or damp conditions a synthetic fill will be best suited since dampness affects synthetic insulation less than down, allowing heat to be retained even when wet. In cold environments it is not uncommon to wear your insulated jacket on top of all of your other upper layers, so this belay jacket style insulated jacket will need to be oversized to fit comfortably and preferably have a more durable outer fabric to take the wear and tear. For times when moisture is a concern, the insulated jacket should be able to fit comfortably under your shell layer to protect it from getting wet. The weight and thickness of insulated jackets vary widely. You will want to choose the weight and thickness that will be the most versatile to you throughout the year.
The perfect layering system is the one that works well for the individual. Adjustments should be made to fit the conditions you will be encountering as well as taking in to account of how warm or cold your body tends to run. Regardless of whether you are a hiker, climber or skier this layering system will be versatile and work well throughout the year in your backcountry travels.