Merging of Espresso and Practice — ISSW Part 2

ISSW, Innsbruck 2018. Alas, jetlag caught up and today I arrived late despite a few cups of power fluid. That means I missed “Localized Dynamic Loading in Extreme Snowmobile Maneuvers.” I do have the abstract. It is worth summarizing.

The gist is that the power and capability of snowmobiles now greatly exceeds most riders’ ability to assess avalanche danger. This especially in the case of situations such as deep persistent weak layers.

Getting scientific, a study showed that the snow machine exerts 2-5 times the pressure on the snowpack compared to a skier. In other words, want to go trigger an avy? The easiest way would be to boogie around on your sled. Though I’d imagine that skiers doing big cliff drops and high-speed turns might exert more force than this study used as a baseline. And telemarkers shifting all their weight to the rear ski when they ride out that big drop? Off the charts. For that study, ISSW Fernie 2020 will be worth attending.

Next up, I did attend “Investigating Time Scales in Avalanche Formation.” Ever considered exactly when do avalanches run in relation to increased instability, say during a snowfall event? Sure, we count them when the storm clears or morning comes, but that is not the kind of scientific precision our modern avalanche scientists need for their efforts to explain the universe. To that end, these guys laced up a mountain with three kilometers of cable, connecting their sensors. It appeared to me that this was mostly a raw data gathering operation. All will evolve to something enlightening when they have more telemetry along with a multi-year span of data.

Ever wondered a big WHAT? when you’re getting mixed snow and rain? Scott Savage of the Sawtooth Avy Center spoke on forecasting mixed snow and rain… Some of his points that apply well to ski touring:

— Complex forecasting and hazard evaluation.
— Don’t try and solve problems you don’t understand.
— Know this is a challenging situation you can’t fit in a box.
— Perhaps just better to stay home.

Moving along to statistics! For some unknown reason, the conversations I had one-on-one during ISSW often turned to: How many backcountry skiers are there, anyway!? A couple of presentations focused on accident numbers, especially fatalities, but everything suffered without a way to normalize the results for changes in the number of participants. Black hole.

I suggested that researchers simply count cars at trailheads, from weekend to weekend, year to year. I’m willing to bet that would give an adequate take on growth rates, and could even be used to calculate raw numbers. Just having the growth rate would be a huge plus for statistical studies. I’ve estimated that the doubling rate during the past 15 years or so has been about 7 years. Rough guess, but counting cars at our local trailhead bears that out.

Which leads me to a few thoughts. Many of us are wondering how in tarnation we can have our enormous increase in backcountry users here in Colorado, and at the same time see an avy death rate that doesn’t steeply climb as well? (Other states, as well as the U.S. as a whole, may demonstrate this, more or less, but I’ll use Colorado as my point of discussion.) I believe some of this has to do with ski compaction of popular slopes, causing them to slide less. But that’s only part of it. I’m thinking a bigger factor might be that the majority of ski tourers are self-selecting terrain that’s been skied enough to be “tested” and obviously not particularly hazardous on a particular day. In other words, rather than looking for fresh pow on a pristine slope, where avalanche danger is relatively unknown, they go for the slope that other skiers have previously “tested.” I’ve observed this in the field and jokingly called it the sheeple principle (and been one of the sheeple).

A detailed letter from Birkeland, Greene, and Logan in Wilderness and Environmental Medicine describes the situation as follows, for the entire United States: “If we combine a conservative estimate of use increasing 8-fold since 1995 (Lou note, easily true) with our flat fatality trend, then our fatality rate has dropped dramatically. If our fatality rate had stayed constant, we might well be experiencing over 200 US avalanche fatalities each winter.”

What do you guys think? The concept of “self-selection for tested areas” leads to the next section, where my theory clearly did not apply.

“Avalanches and the Law” appeared to be a conference topic of interest to the WildSnow community. One of the more interesting presentations in that regard was titled “Ski Tours — A Legal Vacuum on Fashionable Peaks?” Presenter Klaus Paffeneder held forth with a real-life example. In 2017 an avalanche on the Bosenstain, in Austria. Apparently, this is what they call a “fashionable” tour, meaning it’s crowded, and popular for soloists. The avalanche was triggered near the summit by an unknown and took out three solo skiers. One was swept over a cliff and did not survive. Paffeneder used the accident to support questions that will clearly need answers as ski touring continues to grow in popularity while continuing to use “wild” terrain. I’ll paraphrase his interrogatives for clarity:

– By what standards or “how” do we judge the behavior of solo or group ski tourers? What is criminally negligent? What is socially unacceptable? What is normal?

– Does the general ski touring public understand how loading a slope or mountain with numerous skiers can change the hazard level? Is ignorance an excuse if you trigger an avalanche that takes a life?

– What legal or social responsibility do groups have for each other while backcountry skiing?

– Was the unknown person who triggered the avalanche criminally negligent, as there were skiers below? Were the uphill skiers culpable, in continuing upwards knowing others were above? Is everyone present obligated to perform rescue duties — legally, or socially?

WildSnowers, what is your take? If someone is above you on a peak and they trigger an avalanche that takes you out, any responsibility on their part? Yours? And again, could self-selection for “pre-tested” terrain be the cause of our odd avalanche accident statistics here in Colorado?

(Thanks Blase Reardon for getting me hip to the Wilderness and Environmental Medicine content.)