Author's Note: Okay, as a "treat", I've written a grand ramble.
Part I. The Dynamic Nature of Backcountry Avalanche Forecasting
Backcountry avalanche forecasting is concerned with minimising uncertainty about snowpack instability at a specific time and place. Recreational backcountry skiers are very good at making observations, but often seem confused about how to prioritise their observations. Here are some rules and regulations:
| Datum | Description |
| Class III | Weather Factors. Mostly numeric data; there is high uncertainty about the relationship between weather data and avalanches. This includes observations such as warming, cooling, wind direction, new snow, and rain. The snow may or may not be unstable. |
| Class II | Snowpack Factors. Mostly rule-based data; medium uncertainty about the relationship between snowpack data and avalanches. Includes the results of instability tests ( especially shear quality / fracture character ), snow profiles, ski testing. Are there signs of instability? Is skier-triggering possible? |
| Class I | Instability Factors. Mostly event-based data; low uncertainty about the relationship between instability factors and avalanches. Cracking, whumpfing, avalanches. Skier-triggering is possible. Is there a significant chance of releasing an avalanche of Size 2 or greater? |
Weather Examples
If there is heavy accumulation of new snow, with wind, and warming, and whumpfs, then I'm going to be super careful because I know the snowpack is unstable. However, at this point I don't really care about the heavy accumulation, the wind, or the warming. I'm only concerned with the whumpfing, because it is a crystal clear sign of high snowpack instability.
In this example, I've given the most weight to the observation that reveals direct information about instability. It's also worth mentioning that whumpfs can occur with new snow, cold temperatures, and calm conditions. The endless variety of parameters and outcomes is why weather data has an inherently uncertain characteristic.
In the absence of direct signs of instability, I'd give the most weight to whatever observations revealed the most information about instability. In this example, I would assign a higher priority to recent wind/warming than to new snow amounts because wind can turn small accumulations into thick wind slabs and warming can destabilise the existing snowpack. This is one place where a well-rounded understanding of mountain weather, along with the physical properties of snow, makes prioritisation much easier.
Snowpack Examples
In the case of snowpack factors, I would assign higher priority to shear quality / fracture character than to the number of taps in a compression test. Mostly because the number of taps only provides indirect information about instability ( an index of instability if you will ), whereas shear quality/fracture character reveals fairly direct information about instability. I use the extended column test in a similar fashion. It's important to note that research in Canada ( by Cam Campbell et al. ) has found that there is less variability with respect to shear quality than for the number of taps.
The Avalanche Handbook compares improper use of snowpack tests to the lottery and Russian roulette. For this reason, and for other reasons that I won't discuss here, I really don't use snowpack tests or formal profiles all that often because I'm really only looking for a few specific things when I dig:
- What is the layering?
- What are the crystal forms?
- Does hardness increase uniformly with depth?
I perform formal snowpack tests only when I'm curious about the shear quality and fracture character of something specific. Very often, finding a weakness is enough to make me strongly consider alternate plans without the need for actually testing the weakness. I suppose this is my way of saying that I assume it is possible to release avalanches on most weaknesses.
For the record: I'm providing this information here as an example of how I prioritise observations and sort out red flags; this is just my personal style. You probably shouldn't do things this way unless you understand snow metamorphism from cloud-to-ground.
Backcountry Avalanche Forecasting Is Dynamic
Anyway, this leads to the next concept: the dynamic, ongoing nature of backcountry avalanche forecasting is one thing that quite a few recreational backcountry skiers don't understand very well. I have actually witnessed backcountry skiers comparing and contrasting signs of stability with signs of instability. Backcountry avalanche forecasting is framed around instability, and searching for signs of stability ( AKA "searching for supportive evidence" ) amounts to doing it backwards.
And feel free to disregard redundant information: research by Makridakis shows us that while additional information can increase your confidence in a conclusion, the relationship between confidence and accuracy is tenuous. Futhermore, Makridakis found that redundant information can actually decrease the accuracy of predictions. The correct procedure: continually revise your forecast as you integrate new observations. Continually ask yourself, using the data interpretation guidelines above, does the data reveal anything about instability? A single piece of data that reveals information about instability has the power to completely change the forecast from "potential instability" to "high instability". New plans are in order if that's the case.
Regardless of any of my prattling, make conservative decisions when your uncertainty is high for any reason. High uncertainty is a sign that you lack the information required to make sound judgments about risk. And remember, desire and uncertainty are an especially dangerous combination when unmanaged.
The rest of the post contains musings and additional information. There is a lot of opinion, so please take it with a grain of salt.
Part 2. How Do I Learn Snow Safety?
Okay, it's time to get out the salt. Keep the salt out until the very end of this post.
Having resumed posting for the season, people have started asking questions about how to learn snow safety. With good reason, most people will never have the interest in or need to develop a professional level understanding of snow safety, but that doesn't mean they aren't interested in gaining a deeper understanding. Maybe it's because they love powder skiing, ski mountaineering, or powder skiing mountaineering. Maybe it's because they love their friends and family.
I'm not sure how to answer this question because I learned snow safety through a blend of frozen fingers, the terror of bad decisions, and lots of studying. If I had to do it all over again, I'd set the following goal: develop a reasonably detailed mental model of the physical processes taking place in the mountain environment. Here are the main study areas:
| Learn About | Description |
| Yourself | Invaluable since we create the hazard. Incredibly difficult. Easily #1. ParksCanada has maps of popular backcountry skiing locations and one of maps actually asks the user "what brings you here today?". In a similar vein, Martin Volken gave a talk at the 2008 Northwest Snow & Avalanche Summit. His presentation asked "why are we going to the mountains?" It was a wonderful talk. |
| Snow Metamorphism | From cloud to ground. Utterly invaluable. Better learned while in the kitchen with a hot coffee and toast than from inside the belly of the white whale. ( Free study material. ) |
| Mountain Weather | Mountain weather. Invaluable. It's probably easier to learn in the safety of your living room. However, you can also learn a lot about mountain weather by standing on a ridge top while 130 km/h wind sucks the air from your lungs and resurfaces the skin on your face. Yes, afterwards you'll look younger on the outside, but you'll feel older on the inside! ( Free study material. ) |
| Avalanche Forecasting | Avalanche forecasting from Chapter 6 of The Avalanche Handbook. The material is simply amazing and it will help you tie your knowledge together brilliantly. You know what, I'll be honest, it's a tough chapter but it's not certainly not even in the same realm as algebra. It's also not as tough as thinking about how your boyfriend of 15 years will react if someone tells him that you've been killed by an avalanche. ( More free study material. ) |
My bottom line advice: start out with an AIARE Level 1 class if you're in the US. Check with the CAA if you're in Canada.
Learning About Yourself
This is important on any number of levels, especially if you'd like to get married and stay married. It's also important because learning about yourself teaches you so many things. As with everyone who is approaching 40 as quickly as I am, my personal journey could fill a book or two. Actually, the mistakes alone could fill a book. ( Or maybe two books. But definitely not a library. At least I hope not. )
In all seriousness, I have had my share of moments, including days spent gliding through snow that was hovering right at the razor's edge of serious instability. Gain enough experience and you'll learn what snow feels like when it wants to move. Learn enough about yourself and, unlike me, you'll probably be smart enough to avoid that situation in the first place.
Bottom line: Backcountry avalanche forecasting is much easier when you stop eating idiot sandwiches ( and I ought to know! ). Give introspection and inner peace a chance.
Learning About Snow Metamorphism
I sometimes hear people talk with disdain about the subject of snow metamorphism, especially during conversations about avalanche education. What is snow metamorphism anyway? Well, I have a fairly inclusive definition of snow metamorphism. To me, snow metamorphism starts during crystal formation in the clouds and it ends when the last of the snow melts in the summer. But at any rate, it seems to me that a great many people confuse snow profiles and snowpack tests with snow metamorphism when they're not even remotely the same thing. Snow metamorphism describes how the snowpack forms and understanding the physical properties of snow, including its behaviour from cloud-to-ground, is incredibly useful.
If you don't understand snow metamorphism, then the vague results often associated with snowpack tests aren't very useful. Of course, if you don't understand snow metamorphism, you won't understand why snowpack test results are often vague any more than you'll understand why snow metamorphism is so important in the first place. People who understand snow metamorphism from cloud-to-ground rarely base go/no go decisions on a snow profile. Why is that? It's because they understand the inter-connections between terrain, snowpack, and weather.
Is it important to observe crystals as they fall from the sky? Yes, it certainly can be very important, especially if crystal size increases markedly during a day of powder skiing. This is a sign that a warmer temperature regime is passing over the mountains, and warmer air carries more water vapour. If the day started out cool, an increase in crystal size can indicate the potential for upside down snow. What about poking around in the snow and observing crystal forms? Yes, also important. After all, the snowpack is a living, breathing beast that you must understand if you want to play in the mountains during winter.
Bottom line: Learn about the life cycle of snow.
Learning About Mountain Weather
It's complicated, right? That's putting it lightly indeed. Mountain weather teaches you a lot about snow safety because the unreal complexity of mountain weather—especially the chaotic interaction of weather and terrain—is incredibly humbling. Once you understand the complexity of mountain weather, it's much easier to understand why the snowpack is so complicated. Once you understand the adiabatic lapse rate... well... actually cold air advection is more interesting, but at any rate.
Once you accept the complexity of the interaction between terrain and weather, and its effects on the snowpack, you'll know—I mean you'll really know deep down inside—that it's utterly and stupidly pointless to try and outsmart the snowpack. You'll be forever done with all that pseudo-scientific speculation that always happens during water breaks because you'll understand what you can't know and why you can't know it. Spatial variability won't be a puzzle; it'll simply be what is.
With enough knowledge about, and experience with, mountain weather, it is possible to discern patterns of instability and gain valuable insights about where you shouldn't travel. But here's the thing: having enough knowledge and experience about mountain weather will almost certainly convince you that discretion is the better part of valour.
Bottom line: Mountain weather will amaze and humble you. Learn mountain weather basics for free. Or learn about avalanche weather for free.
Learning About Backcountry Avalanche Forecasting
It's funny how often I answer the same questions. I've even written posts on this blog to answer the same question after it was posed to me by three different people. Last season I received about 100 questions, and most of them were related to backcountry avalanche forecasting. Occasionally the question will involve a dispute between two parties who couldn't agree whether or not they made the right choice for a go/no go decision. Myself, I like to stay out of disputes, so I always decline to answer those questions.
I'm not really sure about the level of knowledge or experience of the people who ask questions, but it is always very clear to me that these nice folks don't have a very good understanding of how backcountry avalanche forecasting works. The questions invariably boil down to the following: I have these observations; what should I do in this situation? As I said above, most recreational backcountry skiers are very skilled at making observations, but far less skilled at prioritising. Prioritising observations is exactly how one minimises uncertainty about instability, and therefore it is at the very heart of backcountry avalanche forecasting.
If you read this blog with any regularity, you are probably well-aware of my near fanatical devotion to The Avalanche Handbook. However, in this case I'm going to make a rare criticism. The chapter on backcountry avalanche forecasting ( called "The ABCs of Backcountry Avalanche Forecasting ) is a confusing mix of weird rules, strange procedures, and useful facts. I didn't really learn anything that I didn't already know, and while I think you should still read the chapter, I've probably read it a dozen times, and it's never made much sense to me. ( I could be stupid! )
Luckily, chapter 6, ( called "The Elements of Applied Avalanche Forecasting" ) is quite brilliant. The authors are quite careful to note that the chapter outlines a theoretical framework for avalanche forecasting, but whatever the case, it just so happens that their theoretical framework is pretty damn excellent.
So, if you want to learn how to integrate observations in order to forecast avalanches, you should study chapter 6, and you should study it hard. I can think of no better learning material. Yes, there are clear differences between office-based forecasting and backcountry avalanche forecasting, but chapter 6 teaches you how to approach the subject with a very professional discipline.
Which certainly won't hurt.
Conclusion
Studying mountain weather, snow metamorphism, and avalanche forecasting will help you develop a detailed mental model of the mountain environment. Studying yourself will help you understand the role your psychology plays in the choices you make. For obvious reasons, it's best to study all the subjects I've discussed here, but I'd choose to learn about myself if I could only pick one.
Sometimes people ask what motivates me to write blog posts and do research ( most of which I do in my spare time, unpaid ). I do this because I know exactly what it feels like to stare death in the face. On a few occasions it might have been my own death, but that never really bothered me all that much. I don't say this because I'm fearless; the truth is that during any such situation I was simply too scared to really think about anything other than getting out.
But it's really scary to stare someone else's death in the face. It's even more awful to feel their death slowly take you down into the darkest places you can imagine. I've been there too, and honestly, few things are worse. This is what motivates me to teach myself.
I guess that's the price of love.
I know it's not cheap.
No comments:
Post a Comment