I have become quite good at assessing the quality of snow but usually it’s not until evident what I will be dealing with until I’m already packed and out in the backcountry. Too late to turn back, so we soldier on, making the most of what is already packed and the gear we have with us. Wind slab on a backcountry skiing day? Keep moving, stick to the trees if you can. Punchy snow while fat biking? Let some air out of the tires. Such is the nature of winter adventures, unpredictable, often 'type 2' fun. Best to come prepared for a wide variety of challenges. I’ve listed here some of the challenges you might experience and the layering systems that work best for me.
I always bring the clothes on my back plus a backpack with spares or alternatives:
Top: Alpine Fit base layer, thin synthetic puffy mid layer, Gore Tex Shell, down puffy packed
Bottom: Alpine Fit base layer, sometimes fleece shorts if the temperature is super low or my exertion level is minimal, Gore Tex or Schoeller shell
Head: Alpine Fit hat and neck gaiter, goggles, face covering packed for emergency. Usually a backup headband, it's lightweight and great for heavier exertion days
Hands: one pair of lighter gloves and another pair of thick mittens, hand warmers packed
Feet: Wool socks, boots to match your adventure, toe warmers packed or already on if <0F
If planning a day at altitude, always best to look at the top of the mountain before you go or at least on your drive. Lenticular clouds (smooth lens-shaped clouds) are a bad sign, expect very high winds. Snow blowing over the top can mean the same but you might find respite in the lee of the mountain. Remember that wind chill drops the perceived temperature significantly and cause frostbite fast so expect to bundle up thoroughly. 3 layers on top minimum, with Alpine Fit base layer shirt, synthetic puffy mid layer, and Gore Tex shell. 2 layers on bottom with Alpine Fit base layer and Gore Tex or Schoeller shell. I use a synthetic puffy because I expect to be sweating and it will dry better and more quickly. I also usually bring a thicker puffy for lunch breaks. On the coldest days I’ll wear my super awesome fleece shorts (custom). Take your neck gaiter and a warm fleece-lined hat. Bring some goggles as well, not just sunglasses. Depending on the temperature (less that -10F) a face mask can be nice, but your neck warmer (or 2) may also work.
Sunny and Calm
These are some of the best days in winter and often the easiest to predict. Sunny weather often follows bad weather and sticks around for a few days giving some stability to the system. It also means a high pressure and cold, so bundle up when you're not moving. This is the best time for your puffiest layers. Bring your Alpine Fit base layers top and bottom. Mid layers include fleece or down shorts on bottom and synthetic/down thin puffy mid, and a shell to lock it in. My thick puffy is big enough to fit over all of that so I don’t have to strip to put it on. A good thick Alpine Fit neck warmer and hat as well of course. You may get away without goggles or face mask but I usually have them in my backpack just in case. Finally, remember that you may not get much solar warmth in the middle of winter, especially in early January; March on the other hand can be quite pleasant.
It’s a vague term and I’ll use it here to imply snow, sleet, cold rain, freezing fog etc. These are challenging conditions. Visibility is often poor, the ‘wet cold’ feels colder than it actually is, and the snow conditions can make your preferred mode of travel more difficult. I find I sweat most on these days so expect to be a little damp inside and out so the right fabrics are important. Bring warm footwear, often with toe warmers. The usual Alpine Fit base layer plus synthetic mid layer and a good shell top and bottom. Wear goggles that help in flat light, but they often get fogged or even iced up in these conditions. Make sure all your gear is breathable and it’s okay to take the extra time to adjust layers to maximize ventilation. I often find it helps to move a little slower to prevent excessive perspiration and keep moving to avoid the chill that sets in quickly.
Good luck out there!