Avalanche Safety for Backcountry Travelers

[Stephanie Jordan]

Companion forum thread to:

Avalanche Safety for Backcountry Travelers

[Billy Ray]

here's another great avalanche class:

http://donnersummitavalancheseminars.com/

Billy

[Andrew F]

An excellent and timely article. Thanks Kevin.

[Ian]

Great article!

[Roger Caffin]

To the best of my knowlegde, there has been just one avalanche in the Australian snow fields over the last 20 – 40 years. I have no idea why, and I suspect >99% of our ski tourers never even think about avalanches.

So interesting stuff, but not something we see in Oz. Weird.

Cheers
Roger

[John S.]

Australia may have less natural triggering events such as natural seismic activity, earthquakes, blizzards.

[Jonathan Shefftz]

I strongly suggest that anyone really interested in safe winter travel disregard this article and instead first read either the book by Bruce Tremper that I assign to my avalanche course students:
http://www.mountaineersbooks.org/Staying-Alive-in-Avalanche-Terrain-2nd-Ed-P512.aspx
… or his new book that is on a more introductory level:
http://www.mountaineersbooks.org/Avalanche-Essentials-P1170.aspx

If you do read this article, then here are some corrections for some of the most egregious aspects:

1. I count seven references each to beacons and probes, yet not a single reference to shovels. Maybe the implicit assumption is that each and every winter traveler will already have a shovel, but still, this has to be some kind of first for an article about avalanche safety to omit any reference to shovels.

2. “Let’s dispel a few myths. […] Second, most avalanches do not kill by burying their victims. They are more likely to kill by sending an unsuspecting skier over a cliff or by smashing them into rocks or trees.”
– Exactly the other way around, i.e., the usual statistic is about 3/4 asphyxiation (via airway burial) versus 1/4 trauma. (Avalanche deaths for technical climbers can be more like around 1/3 trauma, but the only study I’ve ever seen for a majority of avalanche deaths via trauma is my own analysis of deaths on NH’s Mt Washington.)

3. “Slopes with angles between 25 and 40 degrees of steepness are the most prone to avalanches.”
This statement is very misleading, and the accompany diagram from some book is even worse, both for its portrayal of slopes between 40-45 degrees, and the misuse of the word “Moderate” in this context, since it is one of the descriptors on the five-point avalanche forecasting scale.
The statement is contradicted even by the accompanying diagram, as well as by the typical classification, as found in the older Tremper book:
“Slopes between 35 and 45 degrees cause the vast majority of avalanche fatalities […]. Recent statistics from Canada and Switzerland indicate that half of human-triggered avalanches occur between 37 and 42 degrees […].”
… by his newer more introductory book:
“In the steepness graph […], the bull’s-eye steepness is 39 degrees; nearly three out of four avalanches occur in red-light starting zones (34 to 45 degrees), 10% occur in the yellow-light terrain on the gentle side of the curve (30-34 degrees), 13% on the steep end of the curve, and only 3% on slopes less than 30 degrees.”

4. “If you take an avalanche course you’ll be taught about digging a snow pit to assess for unstable layers.”
Teaching snowpit assessment skills is no longer part of the standard Level 1 three-day curriculum.

5. “In the Sierra we get a very heavy “marine” snowfall […]”
Tahoe does have a maritime avalanche climate, but not the Eastern Sierra.

6. I’m not going to get into the snow science aspects of the article except to note that depth hoar often seems to be confused here with buried surface hoar.

[Jonathan Shefftz]

"Australia may have less natural triggering events such as natural seismic activity, earthquakes, blizzards."
— I have no idea if Australian above-treeline terrain is less susceptible to snowstorms with heavy wind … but I do know that most avalanche fatalities are from human-triggered avalanches, and of naturally triggered avalanches, natural seismic activity / earthquakes are an extremely rare cause (e.g., 1970 Huascarán).

[Eric Blumensaadt]

Kevin,

Excellent article with great illustrations. As an avy certified ski patroller in an avalanche prone area (Las Vegas Ski & Snowboard Resort in Lee Canyon, Spring Mountains) I applaud this timely article as not only intertesting but necessary for those travelling in avy territory.

MINIMUM AVALANCHE SAFETY KIT:

1. Avalanche One course
2. avy beacon
3. probe
4. avy shovel (no plastic blades)
5. snow study kit (inclinometer, compass, magnifier, thermometer, etc.)

RECOMMENDED AVY GEAR:

1. snow saw (for Rutschblock and snow pit study)
2. Avalung
3. avy air bag backpack (BCA pack, for ex.)

Then go out with other similarly equipped friends and PRACTICE.
Practice finding a hidden beacon.
Practice team digging for buried beacon using > shaped digging technique and "paddling" movement of snow.

IN AVY TERRAIN:
Practice maximum caution for route selection. Testosterone-charged macho attitudes lead to abandoning proper caution. This is why groups that include females have a much lower chance of being avalanched. (true)

Again Kevin, thanks for a great article. This article, with any needed updates, should be posted EVERY year at this time.

UPDATE: Worldwide statistics show that those avalanched with DEPLOYED airbags have a 90+% chance of survival. Most of the data comes from Europe and North America. The European avy areas are much less forested than in North America. Therefore the statistics are somewhat skewed by the European data. Still, even with an 80% chance of survival an airbag pack should be virtually mandatory for any commercial heli-ski operations and "highly recommended" for backcountry skiers.

[John S.]

Does one typically learn how to really use a snow study kit in an avalanche one course?

[Bob Gross]

Every avalanche course is different, and they are different across different parts of the country due to huge differences in the makeup of snow.

Sometimes a whole snow study kit is demonstrated in a first-level class, but often it isn't used until a second-level class.

A few of us managed to study the snow very quickly on our first unexpected ride down the hill. For my second event, I had the opportunity to study the snow from the underneath.

–B.G.–

[Kevin Sawchuk]

Jonathan:

Thank-you for your comments. You obviously have a great background of snow safety. You are absolutely correct, not including a shovel as required gear in avalanche terrain is a major oversight. If you need a probe and beacon you need a shovel to explore for the person (or body) buried. I always carry one and absolutely agree that a plastic bladed shovel is inadequate. When avalanches come to rest the snow is in a very compacted state that is difficult to dig through. I have asked the article be updated with this important point.

I won't debate the other differences of percentage of victims (killed and injured) by burial vs by terrain. The important point is to pay attention to the terrain below you as a very small slide can send you places you don't want to go.

What I was trying to capture in the slope angle is that since we travel much more frequently in more gentle terrain we're more likely to trigger slides in more gentle terrain. It's easy to think of 30-35 degrees as "safe" and not requiring special attention. This type of relaxed attitude is what gets you killed. Only hard core skiers ski 45 degrees–it's double black diamond steepness (and personally very fun) but not visited by snowshoers and backpack tourers often.

Thanks for shedding light and knowledge!

[Kevin Sawchuk]

When I took my level one course ~5 years ago snow pits and avalanche study kits were covered. Given how differently snow can behave short distances apart I usually dig only 1-2 snow pits per trip just to get a sense of what is happening deeper but I rely on the general information and terrain aspects most.

[Billy Ray]

Since this site is about saving weight, there is another strategy with regard to the shovel…

Leave it in the car, but make sure the others in the group have shovels! You can save quite a bit of weight…

Think about it. :)

[okay… maybe bad joke on a serious subject… ]

Billy

[Kevin Sawchuk]

Billy:

Same reason I'm always willing to loan my triple antenna beacon to a newbie with a lesser device! If it's needed you want the person looking for you to have the best.

[Billy Ray]

Kevin…

I have a similar situation with a very old Ortovox and a last year beacon and have had the same thought… great minds (or devious ones anyway) think alike… eh?

Billy

[Stuart R]

Every avalanche course is different, and they are different across different parts of the country due to huge differences in the makeup of snow.

Indeed, and in different countries too. Here in Scotland windslab avalanches are the most common, so it is important to know the recent wind and temperature history when going out.
The classic text for Scottish conditions is A Chance in a Million?

[casey redder]

The avy 1 class i help teach every winter covers the basic whats whys and wheres of avalanches and i think it is a good starter to get people thinking about the mindset you must have in the backcountry…
We teach a go/no-go system, where if one person has a concern about terrain, weather, etc. then the group shouldn't do it… find different terrain to play on.
We also do a full day on gear, from all the manufacuturers, BCA, PIEPs, Mammut etc… the students are encouraged to touch and use all the beacons during the beacon hunt.
Then we do an on-hill day where the students get to use probes and get a feel for what a helmet feels like or a boot or even a torso. Then we dig pits in many different aspects, south facing no trees, north facing in the trees, above and below rock bands (at a ski area so the chance of an avy is minimized of course) just to show someone new to the winter side of BC fun that different parts of the mountain behave differently when it comes to snow. Finally they get to move to a scenario where we've buried some beacons and synthetic humans in snow cat debris and turn them loose… everyone gets to enjoy digging in avy-crete with metal shovels, plastic blades and plastic shovels… by the end the plastic stuff is on the sidelines… i like to finish it off with a quick CPR refresher and some basic first aide while they're still sweating and panting, oh and remind them that they could be miles from thier car… so digging someone out is just the beginning of the fun.

[Bob Gross]

What some cross country ski groups do is to have a transceiver practice in sloping sand dunes. Basically, one transceiver is left in the transmit mode, and then placed in a plastic bag, and then buried in a sand dune. Then the sand is smoothed over. The trainees arrive, switch over to receive mode, and then look for the target.

It doesn't take too much practice to get the hang of it.

–B.G.–

[John S.]

Sounds like a great course Casey.

[Daniel Paladino]

Kevin, Excellent article. This is obviously geared toward beginners, and the concepts you illustrated provide a very good stepping stone to more advanced education.

One MAJOR concept that should be included when discussing avalanche terrain is slope convexity vs. concavity. Convex slopes, even if the they start at shallow angles, are exceptionally weak, and can act as dangerous trigger point for much larger avalanches. More info here: http://www.fsavalanche.org/encyclopedia/convex_slope.htm

[Kevin Sawchuk]

Yes. Excellent point that I could have made more strongly. Micro terrain dictates significant differences in risk. You've got to develop an eye for it.

[icefest From Australia]

>To the best of my knowledge, there has been just one avalanche in the Australian snow fields over the last 20 – 40 years.

I think small slab slides are not that uncommon.
The Aussie ski forums have several reports of near misses.

I definitely agree that Aussie ski tourers are worried much less about them than those in the states.

http://forums.ski.com.au/xf/threads/avalanche-rescue-on-bogong.22624/
http://forums.ski.com.au/xf/threads/avalanche-risk-australian-backcountry.49574/

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