Layering for Backcountry Ski Touring

Me wearing a thin wool T-shirt and vented softshell pants on a very warm spring day.

Staying comfortable in variable conditions

Backcountry skiing requires clothing that works as a system to keep you comfortable in a wide variety of conditions. A long ski tour might start in warm, sunny conditions at a low elevation trailhead and take you thousands of feet higher into a full-on winter storm. You may find yourself overheating while skiing up a steep slope with sun reflecting off the snow at you from all angles and minutes later huddling in the lee of a small rock to escape from freezing winds while you eat enough to keep you going.

No two trips are alike and weather forecasts are frequently wrong. Here are a few examples of clothing systems we bring on different trips, and why they work for us. These systems are all based on idea of a minimal "action suit" that you wear for protection from the elements while skiing and booster layers that you add on top of it at stops or when it gets really cold.

Soft shell from head to toe in winter. 

The Basic Ingredients

1. Wicking base layers that absorb sweat to keep it from evaporating directly off your skin. Merino wool is our favorite choice in this catagory as it doesn't feel as clammy or smell bad as quickly as synthetic fibers. 
2. Moisture moving mid layers. Thin fleece that is smooth and dense on the outside and has a grid pattern on the inside works best for this. Air on the inside is kept warmer and can flow through the grid, picking up moisture which will be deposited on the outside of the dense fleece where the air is forced to cool off.
3. Shell layers that seal out the weather and seal in the heat yet let moisture escape. Because ski touring involves working hard and sweating, we prefer highly breathable thin soft shells over fully waterproof coats.  These layers also create a micro climate that helps your inner layers move moisture. These  can be divided into hardshells that are fully waterproof and softshells that are only water resistant but offer better breathability. 
4. Booster insulation layers that are added on top of the above when additional warmth is needed. These layers should ideally keep you warm enough at rest stops to dry your inner layers and be versatile enough to use while moving in the coldest conditions you will encounter. It used to be common to add fleece layers inside your shell but modern down and synthetic puffy layers offer enough weather resistance to be added on top of your shell as needed.

The action suit idea was popularized by Mark Twight's "Extreme Alpinism" which is a great, if opinionated and somewhat outdated read for anyone going into the mountains.

Top Layers for Winter Conditions

Top Layers For Cold Midwinter Conditions

The photo above shows top layers I've used for a tour where I expected temperatures below 20F with wind and little sun. From left to right they are:

1. A warm cat who will wait for you at home.
2. Sun hat and sunglasses. Mountain sun is bright and snow makes it brighter even on cloudy days. Don't rely on ski goggles alone as they are too warm for use on long uphills. I carry dark sunglasses and amber goggles which gives some options.
3. Stoic Merino Bliss 150 Shirt. This is a thin merino wool top. Lots of companies make tops like this but I am fond of this one because it has a chest zipper for venting, thumb loops for adding warmth to gloves and a chest pocket that is useful for keeping things warm inside your clothes (like a blood test meter or energy bar).
4. Patagonia R1 Hoody. This is the canonical piece of griddy fleece insulation. It moves moisture exceptionally well and has thumbloops and a hood that is perfect for wearing under a helmet and can be used zipped up to keep your neck warm or loose to keep your ears and head sheltered without overheating your core. It is a bit warm for spring and summer use so Patagonia has released a thinner griddy fleece Capaline 4 Hoody. Other companies including North West Alpine and MEC have similar hoodies but the r1 was the first and remains the standard.
5. Patagonia Ascentionist Softshell. This is a thin, uninsulated but weather resistant and extremely breathable softshell. It was discontinued because the welded seams did not hold up to the high heat of a dryer well, but remains one of our favorites. It breaths well enough that I frequently wear it  while skiing uphill to accelerate the rate at which moisture passes through my inner layers, yet provides enough water resistance to allow us to leave the hard shells at home even in typical Cascade conditions (we occasionally refresh the water resistance with a spray: Granger's or Mcnett's, not Nicwax). Patagonia, Rab and Black Diamond have some new models that look similar. Key to the Ascentionists versatility is the use of a non membrane softshell for maximum breathability and the lack of any sort of insulation.
6. Warm hat. I like a hat that entirely covers my ears and is thin enough to fit under a helmet. The one in the photo is a Mountain Hardware hat I cut the tassel off of. Sometimes I supplement it with a head band or folded neck gator that will keep my ears out of the wind without keeping me too warm.
7. Patagonia Nano Puff Pullover. This is a thin (60 gsm Primaloft One) light synthetic booster I use when the above isn't enough to keep me warm while moving...i.e. along ridge lines or after dark. It is weather resistant enough that it functions well as an outermost layer. I also put it on at rest stops to protect my down coat from the moisture in my inner layers. 
8. Eddie Bauer First Ascent Peak XV Jacket. This is a big, warm coat that will keep you warm at stops. You can skimp on this layer if you are near the car or a ski area but for more remote tours you need something that will keep you warm in an emergency.
9. Ski helmet with ear flaps.

Jen descending through a winter storm with a Nano Puff over a soft shell.

Bottom Layers

Bottom Layers for a Cold Trip.

1. Wool or synthetic boxer briefs. Lots of brands work, the extra warmth of boxer briefs around the upper thigh where blood flows close to the surface is nice.
2. Thin Merino Wool ski socks. These are made by Darn Tough but there are a few nice brands out there. Most of the warmth comes from your ski boot liners so these are largely to prevent blisters. 
3. Patagonia R1 Bottoms (Military Surplus Version). Gridy fleece like the r1 bottoms work really well here. I used a thin wool bottom a lot in warmer Cascade conditions but since moving to the Rockies I switched to the R1 and have discovered that is has a much greater comfort range...I've used them and been happy with temps from the single digits to the 30's Fahrenheit.  Jen has the Capaline 4 bottoms which are a bit thinner and apear to be even more versatile for spring and fall use. REI and others also make garments out of the same Polartech Power Dry High Efficiency Fabric.
4. Rab Exodus shoftshell pants. These are non membrane, uninsulated softshell pants. They are on the thick end for pants but have thigh zips that release hot air and catch any cool breeze really well. On some spring trips I use these without a base layer and they are almost as cool as shorts with the vents open. A simpler, thinner softshell pant like the Patagonia Guide pants Jen uses is also a good option and saves some weight.
5. Sherpa Adventure Gear Vajra Panr's. I only bring these on overnight trips or when an extra warm layer is need to increase the safety margin. They are a super simple and light synthetic insulated pant that can be put on without removing my skis.

Warmer Conditions

Lighter top layers for warmer conditions

In warmer conditions like those that might be found on a sunny day, it is important to choose layers that will offer adequate protection against sun and wind without overheating you. This can mean choosing your lightest base layers and bringing a light "wind shell" instead of an insulating mid layer like the r1. It is tempting to skimp booster layers but it is important to have enough of a safety margin in your warm layers if you plan to travel far from the car or ski area. In the photo above I've selected from left to right:

1. Sun hat and glasses. A sun hat that will protect your ears is better, I sometimes use a bandanna or the hood on my windshirt for this.
2. Thin wool baselayer. I like the venting and sun protection offered by this one but bring a t-shirt on the warmest days as in the opening photo. In warm or wet conditions I will sometimes bring two baselayers which lets you swap out the wet/sweaty one. This is especially nice in humid Cascade conditions. 
3. Patagonia Houdini Wind Shirt. This layer is breathable enough for the ascent, yet offers great protection from sun, wind and light precipitation.  I sometimes use it as my only shell and also wear it on some climbs to protect from wind. Another option in this category is the Patagonia Sun Hoody which is even more breathable and offers better protection from sun and wind and a nice big pocket for stuffing gloves or hats into but doesn't have a zipper for venting.
4. Smartwool "The Lid". This is a very thin wool hat perfect for adding under a helmet when you just need a bit of warmth and ear protection.
5. Patagonia Ascentionist Softshell. This piece is redundant with the houdini but offers additional warmth and wind protection and better durability for tree skiing. Depending on the forecast and route I might leave it and bring a light hardshell (that will stay in the pack unless it rains) or an extra warm piece like the Nano Puff instead.
6. Black Diamond Tracer Climbing Helmet. A foam climbing helmet like this offers better ventilation and lighter weight then a ski helmet and is well suited to spring trips and ski mountaineering.
7. Patagonia Hooded Micro Puff Jacket. This is a synthetic coat that will be used at rest stops or in emergencies. Depending on conditions a thicker synthetic coat (i.e. the Das Parka) or a down coat might also be appropriate. Synthetic is better if rain is a possibility and a warm down coat is nice on a dry sunny day that might get very cold after the sun sets. 

Bottom layers for a cold trip will be similar to those for a warm trip though I might not use a baselayer or use a thinner baselayer and choose thinner, lighter colored pants. I also have friends who use a thin nylon pant and add zip sided rain pants when they need more warmth.

Skiing sunny powder in a Houdini, Merino Top, R1 Bottoms and Exodus Pants with Nano Puff and Peak XV in the pack.

What About Hardshells?

The lists above mostly lacks "hardshell" garments that use a membrane like Gortex or eVent to ensure complete waterproofness. I haven't tried the latest generation of membranes (i.e. NeoShell) that claim to offer increased breathability but I have found that the increased amount of moisture inside a hardshell makes them worthless for uphill use in all but constant rain. Even in the typically wet Cascades I usually prefer a softshell with a recently refreshed DWR (McNett's or Grangers work better then Nikwax). It will keep you dry through 30-60 minutes of full on driving rain storm (measured through daily bike commuting use in Seattle) or a day of occasional rain/wet snow squalls and is much better at using your body heat to move moisture from the inner layers out.

Membrane Hardshells do offer excellent wind protection and I have a light one that I sometimes bring to put on at the summit over my Houdini.

What Else?

This post is already quite long so I will cover glove systems and lunch/emergency shelters like Bothy Bags in separate posts. It is also nice to keep a dry cotton t-shirt and sweatshirt in the car for the drive home.