Mark Cohen, March 9, 2021
Author's note: this began as a Twitter thread that spiraled out of control - if it's written a little strangely, that's why.
If you've ever talked to me for more than a minute, you've likely heard me talk about the main passion in my life: backcountry skiing. If you've ever wondered what it is, why I do it, and how I move in the mountains, then this is the post for you!
Some - perhaps many - of you are likely familiar with resort skiing. You go to a ski area with a bunch of lifts and a bunch of designated trails. You ride the lift, ski down, and repeat. Depending on the resort you can get a dozen or more laps in throughout the day. Ski patrol does a ton of work to make sure everyone's safe.
By contrast, backcountry skiing (aka "randonee", "alpine touring", "A/T", or "ski touring") involves self-powered ascents in wild terrain. No lifts, no trails, no patrol. You're on your own.
Self-powered ascents sound simple enough - just walk uphill right? - but in deep snow, walking uphill is nearly impossible. When you sink up to your chest with each footstep, you expend a day's worth of energy moving a hundred feet. Instead, you use specialized gear that allows you to go uphill with skis on your feet. Here's a video of what it looks like:
Let's talk about the gear that goes into making this happen. First of all are skins, which stick to the bottom of your skis. The bases of skis are waxed and smooth; if you try to walk uphill without skins on, you'll just slide backwards. Skins - made of either nylon or mohair - provide directional grip, so that you can drag your ski uphill.
Next, you need to unlock the heel of your boots. When you're skiing downhill, your binding locks onto the toe and heel of your boot. Traditional resort gear only does this. Touring bindings, however, provide two modes: uphill and downhill. The downhill mode behaves like traditional resort gear; the uphill mode disables the heel piece so that only your toe locks into place. The toe piece consists of two pins that allow you to pivot at the toe.
Here's a video of how all this gear works:
That covers the "self-powered ascents" bit, mostly; so let's talk about "wild terrain". In the resort, ski patrol does a ton of work to keep you safe from avalanches. But there's no patrol in the backcountry; nobody's waking up at 3am to go throw explosives into the snowpack.
Avalanches pose a grisly hazard. If you trigger one, the snowpack underneath you will rip out from under you, knock you off your feet, and carry you with it. Avalanches can reach speeds upwards of 80mph - depending on the size, there can be no hope of skiing away. As the avalanche runs, the snow is like liquid; you'll sink underneath because you're less dense. But once the slide stops moving, the snow sets like concrete; if you're fully buried, you'll die of asphyxiation in under 20 minutes, unable to move a muscle or scream. Here's a video of a very lucky skier triggering a large dry slab avalanche:
Mitigating the avalanche hazard starts with knowledge. How and where do avalanches happen?
Fundamentally, an avalanche is snow sliding on other snow. There are many types, but the most dangerous is dry slab. Dry slab avalanches occur when a well-bonded slab of snow slides on top of a poorly-bonded weak layer underneath. With a sufficient trigger (like, say, a skier), the weak layer of snow will collapse, causing the slab to shear away from the surrounding snowpack as the collapse propagates away from the trigger point. For a textbook example of the conditions that cause dry slab avalanches, check out this forecast observation from Utah's recent historic avalanche cycle:
Note: at 0:49, you didn't hear what you think you heard! He said "depth hoar", which is an unfortunately-named type of poorly-bonded snow.
Over 90% of avalanches occur on slopes between 30 and 45 degrees in steepness, with the bullseye coming in at 38 degrees. Unfortunately, slopes between 30 and 45 degrees are prime skiing terrain, which means you have to treat the slopes you ride in the backcountry with exceptional care.
Areas with sufficient resources have avalanche forecast centers. Though I live in Washington, I learned most of what I know now in Utah. The Utah Avalanche Center (UAC) is one of the best in the world, and publishes the most detailed forecasts. Here's a great video from them on how they create the forecast:
The forecast incorporates analysis of the various problems in the snowpack, detailed weather conditions, observations submitted by the public, and more. Here's the first thing you'll see:
This "danger rose" is the distillation of the forecast: at a glance, it gives you a danger rating for a slope at a given elevation and aspect. The danger rating (low, medium, considerable, high, extreme) comprises both the likelihood of triggering an avalanche, as well as the consequences of such an avalanche. For example, a danger rating of "considerable" might mean a low likelihood of a very large avalanche, a high likelihood of a small avalanche, or something in between - it depends on the specific problems in the forecast.
Note: most avalanche centers don't have the resources to make predictions in such detail. Usually you'll see just an elevation profile, without the segments by aspect.
If you'd like to learn more about what goes into forecasts, the UAC has a handy guide.
Now, terrain choice is arguably the most important way that you mitigate avalanche hazard. Terrain choice starts at home, when you're making a plan. It can take the form of asking the question: "given the forecast for today, what terrain is safe to ski?" It can also mean searching for a window of safe conditions to ski a specific objective.
Generally, my process takes the following shape:
There's a lot more knowledge here. There are whole classes you can take! I personally have an AIARE 1 certification, and I'm going to get level 2 as soon as it seems safe given COVID.
But all the knowledge in the world can't control the uncontrollable. There's always a chance of triggering an avalanche, and you always need to be prepared for one. If you get buried, your only hope for survival is being quickly dug out by a partner. So you always need to travel with at least one partner when in avalanche terrain, and both (or all) of you need to know how to perform a rescue.
A successful rescue requires three key physical tools: a beacon (or transciever), a probe, and a shovel. Here's a video of me demonstrating how you use these tools in a rescue:
So what's the payoff for all this risk, knowledge, and specialized gear? The answer is easy: the best skiing of your life. The top-notch quality of terrain and snow that you regularly encounter in the backcountry simply does not exist inside the resort.
I plan to expand the scope of my blog to include trip reports in the coming months. I have a bit of footage from this season of skiing in the central Cascades (though I've unfortunately botched a decent amount of it), and my buddy and I are planning trips up some of the volcanoes here. Stay tuned! In the meantime, here's some glam footage of the last thing I did before the pandemic, which was ten days of deep powder in the Hokkaido interior, Japan. This was a guided group backcountry trip, with a couple resort days sprinkled in on high danger days.
This work is licensed under the CC BY-NC-ND 4.0 license.