Stretch-woven soft shell fabrics are the best choice for all-purpose cold weather shells.
This is the sixth in a series of articles outlining a simple clothing system for outdoor recreation. An overview of the system is offered here. Topics covered include baselayers, lightweight fleece insulation, midweight insulating jackets and wind shells.
When I started working in the outdoor biz back in 1991, there was an idea going around that you could have one waterproof/breathable shell jacket that would work for all conditions. After years of development, Gore-Tex fabric had become breathable enough and waterproof enough that it seemed like it might be possible to use a single Gore-Tex shell instead of carrying both a mountaineering parka and a waterproof shell on backcountry trips.
Up until this time, waterproof clothing had generally been considered a specialty item in a layering system–a last resort if it was pouring down rain. The lack of vapor transmission through traditional waterproof jackets meant that under high exertion perspiration would build up inside the shell and soak insulation layers. Waterproof/breathable fabrics promised to eliminate this problem and reduce pack weight for outdoor enthusiasts.
Most of us who came up in the outdoor industry at the time fully adopted the Gore-Tex shell fabric concept and did our winter adventuring in waterproof/breathable shells. Looking back, they never did seem to work as well as advertised. Under ideal conditions with the correct temperature, humidity and exertion level, waterproof/breathable fabrics can effectively pass water vapor from inside to outside the shell fabric. Unfortunately, conditions are seldom ideal in the outdoors.
The biggest problem for most folks is that waterproof/breathable fabrics simply don’t breathe well enough to keep up with perspiration during high exertion activities. Anyone who has taken a rainy, warm weather hike in a waterproof/breathable raincoat knows this well enough. Anyone who has sweltered away in Gore-Tex bibs on a ski tour knows it too. In the cold, waterproof/breathable shells frost up. In the warm, they sweat up. In reality, waterproof/breathable shells don’t breathe well enough to function as a single, multipurpose shell layer.
Twenty five years later this seems like common sense. Back then it didn’t. Our clothing systems consisted of a polyester baselayer, Polartec fleece insulation and a Gore-Tex shell, and we figured that was the best system available. The US Army developed its Extended Cold Weather Clothing System (ECWCS) around this time and fielded something very similar, with Gore-Tex shells as an outer layer to be used in all conditions. It wasn’t until soldiers deployed to the mountains of Afghanistan following the 9-11 attacks that the limitations of this system were demonstrated. Special operations personnel were struggling to stay warm in their issued gear and put in a request to the US Army R&D center to come up with a better solution. This kicked off the development of the Protective Combat Uniform (PCU) in the early 2000’s.
The development of the PCU is discussed in the opening article of this series. In summary, the PCU replaced the waterproof/breathable Gore-Tex outer shell of ECWCS Gen II with a fully breathable, air-permeable soft shell top and bottom. These soft shells were to be used in all cold weather conditions except for sedentary activities in prolonged rain.
Soft shell technology came into the public eye in the US toward the end of the 1990s. Stretch woven fabrics had been in use in Europe before then, but they really came onto the scene in the US when Patagonia rolled out its Regulator layering system in the early 2000’s I first saw the label “soft shell” used in a Patagonia catalog around that time. The term referred to the stretchy, soft fabric used in these garments and served to differentiate them from waterproof/breathable shells, which were subsequently labeled as “hard shells”. Soft shells are stretchy, air permeable and water resistant. Hard shells are windproof, waterproof and minimally breathable.
The idea behind a layering system topped with a soft shell is simple. If you are exerting yourself in inclement weather you are going to be wet one way or the other. If you’re going to be wet you may as well be as comfortable as possible. Breathable hard shells trap moisture inside the layering system and make it much more difficult to dry your insulating layers with your body heat. Soft shells don’t provide much protection from the rain but they breathe so well that you can walk yourself dry once the precipitation stops. In the vast majority of cold weather conditions a person will be much more comfortable in a soft shell than a hard shell.
How it Works
As mentioned above, soft shell fabrics are air permeable. They are wind resistant because of their tight weave but lack a semi-permeable membrane that would make them wind PROOF. The wind will penetrate a soft shell a little bit. This is a feature not a bug.
Soft shells offer plenty of wind resistance. The small amount of air that does pass through them in windy conditions helps to dry your insulating layers. As your body heat drives perspiration away from your baselayer and into your insulating layers, a small amount of airflow helps to evaporate this moisture and keep it moving out of the system. Under these conditions you baselayer dries more quickly. With a dry baselayer you are warmer and feel more comfortable.
Soft shells also avoid the problems of condensation and icing that plague waterproof/breathable fabrics. Waterproof/breathable membranes seal off air flow so effectively that the dew point inside your clothing system shifts all the way to the outer shell. It’s warm inside your layers but the temperature abruptly drops at the thin fabric of your shell jacket. This sharp temperature shift causes moisture to condense on the inside of the shell fabric. Anyone who has experienced frosting up on the inside of a breathable shell knows what this is like. All that frost is moisture waiting to soak your insulating layers.
Since soft shells lack a semi-permeable membrane they don’t develop a sharp temperature gradient at the outer layer of the system. Instead, temperature tends to vary gradually from baselayer to shell. Moisture passes through the system and doesn’t condense on the outer shell. This keeps the wearer drier and more comfortable.
What about Wind Shells?
The main difference between soft shells and wind shells is durability. Soft shell fabrics are heavier that the ultralight fabrics used in wind shells. This means they hold up better for rock climbing, tele skiing and bushwhacking cross country on a backcountry hunt. If you are a three-season backpacker or canoeist you can likely get by without this heavier shell layer. If you enjoy winter adventures you’ll appreciate the added toughness, warmth and stretch that soft shells offer.
Soft Shell or Not
If you start looking for soft shell garments at your local outdoor store you’ll run across a lot of clothes that are called soft shells even though they incorporate some kind of semi-permeable windproof and water resistant membrane. The term “soft shell” has expanded to include everything that is isn’t a fully waterproof hard shell. In fact, one manufacturer I used to work for sold a range of clothing that were billed as waterproof soft shells. They were waterproof, and stretchy and had a fleece lining–a real category bender.
Current offerings from many brands include shells that feature windproof membranes like Windstopper or similar proprietary fabrics. As I suggested in the article on wind shells, and midweight jackets, these membranes are less than ideal. In cold weather any windproof membrane, regardless of how breathable it is, will create the same kind of condensation problems found in fully waterproof/breathable hard shells. For the most functional and versatile cold weather shell, avoid shells with membranes. Stick with air-permeable, stretch-woven fabrics.
Fabrics without stretch can fill the role of soft shells, they just don’t offer as much freedom of motion as their stretch-woven counterparts. Military issue soft shells don’t have as much lycra in their fabric as commercial soft shells, mostly to boost durability in the hands of soldiers. They still function perfectly well as tough, versatile outer layers.
Years ago I experimented with a fully breathable winter shell made from two layers of Versatech polyester microfiber. It was a knee-length anorak sewn from a pattern at the back of Garret and Alexandra Connover’s book: A Snow Walker’s Companion. The anorak blocked the wind, turned away snow and dried quickly. It was a big performance upgrade over waterproof/breathable shells. Wintergreen Northern Wear in Ely, MN manufactures a far more refined version of an arctic anorak that is popular with mushers and winter explorers. Arctic anoraks are fully breathable and air permeable, so they tick the boxes for a proper winter shell. However, their specialized design features make them a little less versatile for a full range of outdoor activities.
Like wind shells, soft shells come from the manufacturer with a durable water repellent treatment on the fabric. This DWR helps to repel light precipitation and prevents the outer shell from soaking through. My experience with DWRs is that they all wear out fairly quickly in the field. Once your shell has been soaked a few times, the DWR won’t be as effective as it was when brand new. DWR can be reactivated by tumble drying your clothes on low (be sure to check care instructions so that you don’t shrink your gear!) or with spray-on or wash-in treatments. I’ve more or less given up on this sort of thing. To me it seems like chasing your tail. Stretch woven fabrics work just fine once the DWR has aged a bit and it isn’t worth my time an effort to constantly try to renew them. I almost always use these fabrics in snowy and cold conditions rather than rainy weather, so the DWR isn’t as critical. That said, if you are concerned about keeping the DWR on your jacket fresh there are plenty of products available to help.
Soft shells offer more features than wind shells. They are intended to be tougher and more functional than the minimalist shells suggested in Layer 4 of this system. Fabrics are heavier for durability and typically feature a bit of lycra for stretch and freedom of movement.
Soft shell jackets will have chest pockets, velcro adjustments at the wrist, drawcord hems and a hood. they may have additional pockets on the chest or sleeve. Jackets should be longer than wind shells–hip length is right. I’m a big fan of hoods on soft shell jackets. Tucking your head into a hood makes a big difference if you’re starting to feel chilled, and a hood keeps snow from dropping off trees and down your collar.
Soft shell pants come in a range of features, often with reinforced cuffs, side zips and ankle zips. Ankle zips on bottoms make it easier to get them on and off over bulky winter footwear and zippers on the upper leg can help with ventilation if you start to overheat. Cargo pockets or flat thigh pockets are helpful spots to tuck a map and compass, bandana or pair of liner gloves. Reinforced cuffs reduce wear from skis, boots or snowshoes.
Stretch woven fabrics come in a range of weights. Heavier woven fabrics are warmer and more wind resistant. Lighter fabrics dry more quickly and are lighter in your pack. Something middle of the road will get the job done. Steer clear of ultralight fabrics that aimed at trail running, these won’t be durable enough for many winter activities and don’t offer the features you’ll want in a winter shell. Also avoid the heaviest fabrics that feature an inner fleece layer. You’re looking for a versatile shell that you can use in conjunction with your other insulating layers and a fleece-lined soft shell will be too specialized. Keep it simple.
Color in soft shells isn’t as critical as it is in wind shells. We won’t be using these shells as sun or bug protection in hot weather, so it isn’t as important to choose a light color that won’t bake you in the bright sun. In fact, in cold weather it can be nice to have your shell soak up a little extra heat if the sun pokes out through the clouds. Choose whatever color makes you happy. Bright colors look good in photos. Drab colors or camo blend in for nature watching or hunting.
Your soft shell layers should be sized to fit comfortably over all the other layers in the system up until now. This means for the top you’ll need to be able to layer over baselayer, lightweight fleece, midweight jacket and windbreaker. For bottoms you’ll need to fit over baselayer and lightweight fleece. For some people this will mean going up a size from what you normally wear. Some companies size their soft shells with layering in mind. Others size them for a trim, athletic fit. It’s important to make sure that whatever you choose will fit over all your other layers without limiting your comfort or range of motion.
Buy This, Not This
You’re looking for a hip-length, hooded jacket in a stretch woven fabric. Pants should be a similar fabric and feature ankle zips for easy on-off. At time of writing good options are available from Outdoor Research, Patagonia and Arcteryx among others. Pick your favorite color.
If you’re looking for an affordable option and don’t mind camo, search the surplus stores for an ECWCS Level 5 jacket and pants. They cost about half as much as commercial soft shell optons. Make sure you look for the non-fire resistant versions. These are lighter and more breathable than the fireproof alternatives.
Don’t by a soft shell with a windproof membrane. Don’t buy a soft shell with an ultralight fabric. Don’t buy a soft shell with a fleece lining.
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