Gear: winter Layers

With winter about to launch in full, and the upper United States experiencing an Arctic cold wave, I thought now is a good time to review some thoughts on how to layer for those winter climbs.

I just got back home from a great summit climb on Mt. Washington in New Hampshire at 6,289 feet. But don’t let the relatively low altitude fool you into thinking its not cold on the top!

“The rock” is known for some of the most unpredictable and worse weather on the planet. On April 12, 1934, the Mount Washington Observatory recorded a windspeed of 231 miles per hour (372 km/h) at the summit, the world record for most of the 20th century, and still a record for measured wind speeds not involved with a tropical cyclone.

When I summited with Chris Ummer, who has 100 summits on the rock, it was not that bad with winds above tree line about 40mph, temp about 10F making the windchill -15F. But the visibility was almost zero for much of the day.

A week before Washington, I summited one of my local peaks, Twin Sisters at 11,427 feet. That day it was very cold, below 0F but there was no wind.

So, we have two very different climbs with different conditions. What did I wear? Basically the same layering system. My general rule of thumb is to never have more than three layers on at any one time and at least one “layer of last resort” in my pack.

Merino_sheepBase Layer – head to toe

This is the key to every layering strategy. A good base layer will wick away sweat, while keeping you warm. It should also feel good next to your skin and the top will have a long zipper for venting. Finally, thumb loops are a convenient feature.

There are several types of materials to select from including synthetics (polyester and polyester blends), silk and wool. I’ve tried all and my choice is Merino wool – hands down, full stop – end of discussion! 🙂

When I look at my base layers neatly stacked on one of my gear shelves, I have tops and bottoms from Icebreaker, Ibex and Patagonia. I have found these brands to be well made, good features and last forever if cared for properly (simple washing every now and then). I also wear only Merino wool skull cap, liner gloves, briefs and socks. If it touches my skin, then it must be … well I think you get the idea!

icebreaker_base_topWhy am I in love with the wool from a sheep? Glad you asked! First, I like how it feels next to my skin. Second, the stuff doesn’t seem to smell. Third, I never seem to get too hot or cold in spite of wide ranging temperature changes. For the record, I wear short sleeve Merino wool tops in the summer.

However, moisture control is the characteristic that always brings me back to Merino wool. I never feel like I am trapped in a sweatshop. It has a magic property of wicking away the moisture before it begins to build. By the way, that is the secret to the no-smell zone. Those stinky bacteria never get a chance to settle in. Finally the lightweight material is easy to cram in my pack. I usually have an extra top stowed away somewhere.

The fact that the individual strands of wool absorb water vapor before it condenses makes it an ideal wicking layer. According to a New Zealand industry group, Merino can absorb up to 30% of its weight in moisture before it starts to feel damp. Its regain factor (the amount of water in the fiber expressed as a percentage of its dry weight) is 17 percent under standard conditions, compared to between 1-4 % for synthetic fibers.

Patagonia_base_bottomSo what is it with this Merino wool and where does it come from?

Merino is a breed of sheep primarily raised in New Zealand and Australia. Selling the wool has tuned into a huge industry. A quick review of the major gear companies that sell Merino wool based products find quick agreement on a few basics: the wool is some of the quality in the world, it does not irritate the skin like traditional wool, it is renewable and easy on the environment and the wicking ability keeps the skin drier.

Merino used to be expensive and not used widely for sports base layers but with competition the price has dropped. Today New Zealand and Australian sheep farmers dominate the market. And quality clothing are available from many of the major brands. In fact Icebreaker has a complete layering system made of 100% Merino wool – very nice.

icebreaker_base_briefThe only real controversy seems to be around how the wool is prepared after sheering. Patagonia explains that each strand of wool contains barb scales that must be removed to prevent skin irritation. Some processes use chlorine to remove the barbs and smooth the material but Patagonia uses a chlorine-free process. Icebreaker, Ibex, and Patagonia all use environmentally friendly manufacturing approaches as specified by the New Zealand MAPP Tech supplier.

Mid Layer

Here is where it gets interesting and where you can have a good discussion (or fight) about what is the  approach.

patagoniahoodyThe mid layer is supposed to trap the warmth your body generates but passes thru the moisture so you don’t get wet and cold. Just like base layers, there are a multitude of materials, designs and features to choose from.

On my recent climbs, I decided to do a simple experiment using two of my favorite Patagonia layers: the R1 Hoody and the relatively new Nano-Air Hoody. There are similar products from most of the major outdoor gear brands.

The R1 is what Patagonia calls fleece or really traditional Polartec material. The inside layer is a basket weave so that it creates an air layer on top of your base layer. This equals warmth and easy movement. They incorporated Capliene 4 stretch panels under the arms, cuffs and hem to increase flexibility but also to reduce bulk – especially useful when wearing a harness. This was my goto mid layer for several years, until …

Patagonia nano-airPatagonia came out with the Nano-Air Hoody. The tag line says “put it on, leave it on” and I am a believer.  It wicks, breaths and stays warm when a bit wet. Nothing else like it on the market imho. Not waterproof or wind resistant in high winds but it my standard mid layer these days.

On Twin Sisters, I did an experiment. I started off with my base layer plus the R1 AND the Nano-Air. As you might expect after 30 minutes I was frying. I took off the Nano-Air and continued with just the base and R1 but was till heating up. Remember the still air temp was hovering around zero but I was pushing my pace and was heating up, unusual for me as I usually run cold.

Around tree line, I thought I would trade the R1 for the Nano-Air. Within 20 minutes my base layer had dried out and I was comfortably warm. My take away: the Nano-Air breathes and insulates better than the R1. This test confirmed why I use it almost exclusively on any day with cold-ish temps.


This is an outer layer where you can get 1,000 opinions from 100 people! Without getting into the debate about what is a shell – soft or hard, and what it is made of Gore-Tex, eVent, Dry.Q, Oh My!; let me try to focus on how I use my hardshell of choice, the Patagonia Troposphere, now sold as the Piolet Jacket (I think).

This top shell is ALWAYS in my winter pack, regardless of the forecast. I pull it put when the wind picks up and/or heavy wet snow comes down. This was my only outer layer on most of K2 and Manaslu, until the summit push when I wore a full down suit.

I’ve learned to be careful, however, when I wear this jacket as if it is too warm or not windy enough, I will quickly overheat.  I know the marketing material reads that these modern shells all breath and will not become a humidity chamber, but I have never experienced that level of comfort.

On Mt. Washington, I had my base, Nano-Air and Troposphere on for all the time above tree line when it was cold and extremely windy. I was comfy.

Last Layer of Resort

While three layers is my rule, I try to be prepared for the worse case scenario – unexpected weather, long delay, injury, bivy. So as for clothing (not emergency gear) in the winter, I always have my top shell (Troposphere), the Patagonia Ultralight Down Hoody, mittens and a full balaclava in my pack. Also, almost always, I include my Arc’teryx Gore-Tex bibs. I did on Washington.

These layers will take me thru a brutal night of cold temps and/or high winds or keep me going if conditions change. The extra weight is nothing compared to saving me from frostbite, injury or death.

Finally, let me add that a serious 800/900 Fill Down Jacket may be in order or even a full down suit depending on the mountain, season, conditions and other factors. This goes for Rainier, Aconcagua, Denali or Everest.

Alan’s Layering Rules

So, for what it’s worth, these are my layering rules I mostly abide by from a Colorado 14er to Mt. Washington to K2 or Everest:

  1. Try to use 3 layers maximum
  2. All jackets have hoods (or at least have 1 hood always available)
  3. Merino wool next to skin
  4. Solid mid layer for warmth
  5. Top layer for wind, snow/rain protection
  6. Gloves AND mittens with liners
  7. Sunglasses AND goggles
  8. Skull cap, balaclava AND buff
  9. Last resort layers in my pack for the unexpected

So there you have it, my approach to layering that I have honed over 20 years in the mountains. I am not saying this system is perfect and certainly I’m not saying it is the only way, but it has served me well from my 14ers to K2 and back home.

Climb On!
Memories are Everything

Summit Coach

If you dream of climbing mountains but are not sure how to start or reach your next level from a Colorado 14er to Rainier, Everest or even K2, I can help. Summit Coach is a consulting service that helps aspiring climbers throughout the world achieve their goals through a personalized set of consulting services based on Alan Arnette’s 20 years of high altitude mountain experience and 30 years as a business executive.

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