|Backcountry Avalanche Workshop 2003:
Speakers and Topics
On Saturday December 6th 2003 the Canadian Avalanche Association hosted
an Avalanche Workshop at the Justice Institute of B.C. BillyGoat and I
attended and found it to be a wonderful source of information.
Authored by: Exscape, Notes by: Exscape & Billgoat
The following are the combined notes of "Exscape" and "BillyGoat" from
the CAA Avalanche Seminar on Saturday December 6th 3003. We did our best to
accurately and objectively convey the information that was communicated at
the session, and like all human beings our interpretation is based on our
perceptions of that information and is subject to some interpretation. If
you are interested in learning more about Werner Munter’s Theories and
Reduction Method keep a lookout for his book. We were told this would be
available in print, in the English language sometime in 2004-2005.
IFMGA Mountain Guide and Director of
the Canadian Avalanche Association
TOPIC: Lessons learned from last year and moderator of the question
& answer period.
The Presentation was begun by Clair Israelson. He defined risk in
backcountry recreation as: Greed/Fear. He went on to discuss the position
that it is very important to tackle risk assessment by first understanding
our own trends or biases with regard to risk. By nature mountaineers are
higher risk takers. This has been a predominantly male enterprise but is
changing. (insert graph)
It was interesting to note that most avalanche incidents occur when the
risk is deemed "Considerable". There are several factors to contribute to
this. When The risk is "Extreme or High" it is pretty cut and dry - if you
don't know or have the skills to read the terrain than most people don't go
period. "Considerable" denotes a middle ground and is a bit ambiguous,
people begin to get overly confident in the conditions and this often leads
to mistakes in perception. Rule of thumb. Considerable or higher demands a
detailed knowledge base of contributing factors to avalanche activity and
the means to identify warning signs in the both in the terrain and the snow
He also went on to clarify that the avalanche bulletins posted by the CAA
is your "guaranteed no bull* promise! "when it's good we will tell you, when
it's bad we will tell you"
Avalanche Consultant, Educator, and
President of the Canadian Avalanche Foundation
Chris Stethem is an avalanche protection consultant
based in Canmore, Alberta. He has spent the past 31 years working with
avalanche programs throughout North and South America and is one of the
senior instructors in the Canadian Avalanche Association Training Schools.
Chris is also President of the Canadian Avalanche Foundation, a Canadian
registered charity raising funds in support of avalanche bulletins,
education and research.
TOPIC: Chris will discuss the human factors in
decision making for travel in avalanche terrain. He will explore risk
perception, situational awareness and group dynamics in the decisions and
actions we take in the backcountry.
"Human Factors" that determine the decisions we make were stressed in
Chris' presentation. He presented three different methods of decision
making/based on risk assessment in the back country.
Skill: Routines stored in memory, this is an unconscious process,
early decisions, and potential for execution error. (highly dependant on the
experience level of the individual)
Rule: Rule or regulation. "If this than do that" thinking. This is
a conscious process - recognise the condition then select a rule or option.
eg: if snowfall accumulation equals 2.5 cm (or 1') of snow per hour or more
- do not go. (could involve violation or mistakes)
Knowledge: Involves problem solving. Good in new situations or
situations without readily available solutions. Evaluate information and
apply knowledge. (potential for evaluation errors or lack or recognising
factors. It is essential to recognise and account for uncertainty)
Situational Awareness: in the field involves three steps.
- Knowledge/recognition of terrain and routes
- Snow stability
- Human Factors.
The CAA uses the acronym "S.T.E.P.S." = consequences/decision
or: Snow, Terrain, Exposure, People in group, Severity
Snow: this is a cumulative process of stability evaluation. Past
knowledge is key! (subscribe to the Avy bulletins via email if you plan to
go out - watch progression of bulletins well in advance of your trip) **the
CAA have plans to add a trends graph and history of bulletins to their
Recognise storm snow and persistent instabilities (most slab avalanche
accidents occur within instabilities in deep snow.) It is not good to expect
a realistic interpretation of conditions from one data point. (applies to
snow block profiling)
Terrain: Which terrain is most at risk? (30% slope and higher)
What are your choices of alternate routes? Our experience on route and in
the terrain in general.
Exposure: How often have you frequented this location, how
familiar is your group with the terrain? What is your mode of travel? What
safety equipment are you carrying? What is the speed and frequency the group
is exposed to such conditions? Catch 22 the more you are exposed the higher
the risk (probability) yet the more you are exposed the more knowledge base
you will gain)
People: Who are we as a backcountry recreation culture? Why are we
out here, what is our goal? Where does each member fall on the risk
tolerance scale? What is the group dynamic?
Severity of Consequences or (what if!): Is there a high risk of a
thin snow pack? Has there been a persistent instability in the snow pack?
(cracks, signs of recent avalanches?)
- perceived level of risk is based on degree of danger felt by an
- the type of past experience associated with the activity (can lend to
- assessment of confidence in understanding potential of immediate
situation is key, or what is your degree of confidence in the decision
your making. If in doubt yield to the least confident in the party.
Judgemental Heuristics: (or experiences that affect our confidence
- what is the frequency of events or exposure
- vividness of memory - has something happened before...
- proximity of information
- casual scenarios of predicted outcomes versus non-events
- mixed information or uncertainty in information gathering/interpreting
Often we fall back on "Representativeness" or:
- Goodness of fit - this happened before...
- first impressions
- pre-existing theory
and unfortunately -
- belief often perseveres over warning signs -( weakness in human
- what is happening with the leadership role?
- what is the group size?
- what are the experiences and skill levels of the group?
- cultural background?
- Hazardous attitudes or "what makes you tick?"
- What is the degree of perceptions with regard to the trip evaluation?
- What is the goal for your group?
- Does peer/media pressures need to be considered for your group?
Your perception of risk is dependant on your personal background.
- consider the influences of peers or media
- consider how you react in the excitement of the moment
Situational Awareness of the Group:
- perception of the the unexpected is often fleeting
- do you feel that something is not right?
- do you feel you should have said something - Then do So!
- Often we are faced with doubts - I thought he/she was looking out
for us, or he/she knew what they were doing...
- choose a leader with the most experience in the terrain or area you
are located. Always speak up! Defer uncertain decisions to the least
comfortable member of the group. (gut feelings)
All Group decisions should be based upon:
- Situational Awareness - Constant assessment
- Recognise Uncertainty
- Generate and Evaluate options
- Anticipate Unexpected Events and their Consequences.
Swiss Federal Institute for Snow & Avalanche
A Swiss mountain guide has authored numerous
technical reports on the subject of avalanches and has been a technical
advisor on snow and avalanche courses for instructors of the Swiss Mountain
Club for nearly 30 years. In 1995, Munter was made an honorary member of the
Swiss Mountain Guides' Association. A researcher with the Swiss Federal
Institute for Snow & Avalanche Research in Davos, Werner’s book 3x3 Lawinen
(German) is officially recommended by the IUAGM and the UIAA and is the
basis for the avalanche training programs in alpine organizations across
TOPIC: Werner will speak about his revolutionary
Risk Reduction Method, which helps people use avalanche bulletins to make
Werner presented several 'Mottos' in the beginning of his
presentation. The one I took special note of was "Expert! Pay attention!
The avalanche does not know you are an expert."
He reflected on 3 different approaches to avalanche forecasting for
recreational skiers and professional guides offer the last three decades:
70's: Experience - common sense and instinct were key. This
involved alot of guesswork.
80's: Analytical/Scientific - Stability tests, profiles, yes/no
decisions based on tests
90's: Strategic Period - decision making based on risk assessment
and human factors
The problem in assessing the snow pack:
Scaled "RB" (Rutschblock test) to measure snow pack stability - scored by
1-5. The idea at the time being that it would be possible to use point
measurements at representative spots and extrapolate the test results to
neighboring slopes. This was based on the belief that the snow pack was
homogeneous, in a similar aspect, elevation and slope angle.
With this method skiers were searching for thresholds for making
Problems/Objections to this method:
In 1984 high and low shear values were found in the same slope along the
fracture line crown of a ski triggered slab avalanche. After examining a
slope for an entire winter. Alain Dulos (a snow scientist an mountain guide)
stated that it is impossible to determine the stability of a slope with only
the traditional scientific approach. This method alone equals "mission
impossible" There is no science for this - how do we measure skill? Between
the years of 1981 and 1991, there were 52 avalanche fatalities recorded in
Switzerland within nine big backcountry ski tours. All of these were
professionally guided. So if the professionals made such big mistakes, there
is something seriously wrong their the approach (comment: There are about
20-25 avalanche fatalities per year in Switzerland, so these big accidents
just illustrate the even professionals were not able to make correct
Conclusions in 1990:
In the 1990s Werner came to the conclusion that the snow pack has to be
viewed as a patchwork of high, medium and low shear values, exhibiting
highly complex spatial patterns. Such patterns cannot be characterized by
single samples, there are no representative locations therefore it is not
possible to define threshold values with one definitive test. An individual
snow profile or stability test is a probabilistic variable. A representative
profile is a chance value. It would only be possible to characterize
these patterns with a large number of samples (e.g. rutsch block test)
which is not really feasible for the recreational skier as numerous route blocks (tests) are necessary in order to be
accurate. It was therefore, clear that
other tools were needed. If we rely on route blocks, multiple tests are
required on steepest slopes. It was time for a new tool for "humble"
Should probably say: (nix the period).."
He bared in mind: based on "bounded mind", "limited time" and incomplete
knowledge of the snow pack. The method had to be easily understood by 98% of
ski tour ops, practical and simple, scientific and "smart".
Werner came up with a new method based on Pattern Recognition.
Risk to be calculated by combined probabilities with small multiplication
tables. Cybernetic or "Operational Knowledge" to generate risk awareness,
contributions of other sciences were utilized in this multi-disciplinary
Munter's Reduction method is based on the idea that there are two modes
of thinking: Scientific or "left" brained; rational, conscious thought,
slow, differentiating, based on scientific details and Operational or "right
brained"; Quick, responsive, intuitive, gut-feeling, based on past
experiences and able to recognise patterns; and the acceptance that we will
need to use both modalities in our decision making processes in order to
make better decisions.
Studies have shown; in order to make better decisions, the maximum of
variables we can deal with is only 3-5, these variables should have no more
than 3-5 different values. More information than this quickly leads to
overload and does not increase the quality of the decision. It is better to
have one basic approach, less details are better.
Munter used Franklin Vestes rule of pattern recognition in creating a
mathematical calculation for determining avalanche potential in a given
area. We must first choose the most important variables, then weigh them
(evaluate) as low med or high then connect the factors with "multiplication"
The Five Key Variables chosen by Munter were:
- Danger Level - reports, bulletins
- Slope angle of the steepest part of the slope being skied/traversed
- Slope Aspect (N, NE, NW)
- Multiple Visible Tracks
- Group size and spacing.
This would equal 5 possible choices in risk reduction:
- Choose to trek out during small danger levels (low, moderate)
- Prefer low slope angles 30-35% (<40 degrees)
- To avoid northern aspects/sectors (N, NE, NW)
- Prefer more heavily travelled terrain (slopes with multiple tracks)
- Go with smaller groups and maintain appropriate distances between
He assigned numerical values to Danger levels represented in the
avalanche bulletin. (=danger potential):
- Low = 2
- Moderate = 4
- Considerable = 8
Risk reduction measures (reduction factors or RF) were also given
First Class RF:
- Activities on a slope below 40% = RF 2 (reduction factor)
- Activities on a slope below 35deg = RF 4
Second Class RF:
- Outside a north aspect (NW-N-NE) = RF 2
- Outside a north aspect (WNW-N-ESE) = RF 3
- Outside all aspects mentioned in the Avalanche bulletin. = RF 4
Third Class RF:
- Spacing between party members = RF 2
- Frequently skied slopes (multiple visible tracks) = RF 2
- Small group size = RF 2
- Small group size with spacing = RF 3
If there is no possibility/choice of reduction than RF 1 is used.
The risk can now be reduced by applying a combination of different safety
measures (reduction factors) under the specific conditions (risk potential)
You can always only apply only one RF from each class.
This method is only valid for travel during Low-Moderate-or Considerable
ratings. Under High or Extreme ratings it is not possible to reduce the risk
down to the acceptable risk levels.
The equation looks like this:
------------- = risk
The goal is to reduce the risk down to the value of 1 or below. This
residual risk is comparable to driving a car or hiking which are socially
acceptable levels of risk. Numerically this residual risk is 1 victim per
100, 000 activities. This means if you have 100 people that all do 1000 ski
tours one of them will get killed in an avalanche.
Example: Hazard rating in avalanche bulletin considerable.
Danger potential = "8"
- and you on a slope below 40 degree = RF 2
- away from a north aspect = RF 2
- and spacing is respected = RF 2
---------------------------- = 1
2*2*2 (multiplication here)
if the risk is assessed at more than 1 the situation is a "no go"
No go rules:
Do not go when:
- The avalanche rating is Moderate, slope is more than 40deg, on a
Northern (Lee) aspect and there are no visible (multiple) tracks.
- The avalanche rating is Considerable and slope is 40% or more, on all
- The avalanche rating is High and slope is 30% or higher (Kick-turn
Human Variables and degree of skill:
- If you choose to be a "risk junkie" there is no room for mistakes.
- More optimal is med risk and higher tolerance for mistakes.
- The other end of this is what Munter called "residual risk" or "too
safe" = no fun
Munter's Matrix for decision making (simplified reduction method
without the math):
Ratings: Considerable=XXX Moderate= XX Low =X
||Dry Snow Conditions
|Wet Snow Conditions
(snow clumps easily)
|Outside Sector North
(NE, N, NW)
||N/A because S aspects are often more dangerous under
(in his research Munter noted that in 60% of all accidents there were no
visible tracks *note plural*)
(10 meters between group members)
So now you just look at the hazard rating to see how many crosses you
need under that rating to equal 1 or less. Then you go through the table and
"collect" crosses by applying certain safety measures.
Examples of the use of "Munter's Matrix"
1. Danger rating = Moderate/ Dry snow/ 42deg slope/ NE aspect/ No Vis
You would need two crosses under moderate conditions, but if you are not
willing to apply any safety measures -> NO GO
2. Danger rating = Considerable/wet snow/32deg slope/spacing respected
You need three crosses under considerable conditions and you get two for
staying below 35% and one for group spacing -> GO!! (The aspect cross is not
available under wet snow conditions)
Since the Reduction Method has become "mandatory" in Switzerland
accidents have been reduced by 55%!
In 1980 - 1995 there were on average 16.7 victims per year. *post
In 1995 - 2003 there have been only 9.4 victims per year. (comment: there
are other factors that have contributed to this decrease.)
These victims include activities such as snowshoeing, skiing,
snowboarding, hiking and ski tours.
Therefore in the "strategic period" there has been a lower instance of
Final notes: If instinct says no = NO GO - no discussion!
If instinct says Yes = Be smart assess risk, use reduction.
- Human factors need to be considered (this means not only psychological
factors but also how our brains work.)
- Statistic models based on rules outperform human experts. Even
extremely complicated calculations can be broken down into simple rules.
*Werner Munter's Book on the reduction method will be available in
English next winter.
Director, French National Association for
Snow & Avalanche Research (ANENA)
Director of ANENA for nine years, Francois
oversees: • Professional training courses • Avalanche educational materials,
conferences and courses for skiers and snowboarders • Research on avalanche
accidents and legal aspects of avalanche accidents
TOPIC: François will discuss the Nivotest, a simple
pocket-size card with 25 questions and a revolving disk that helps users
observe snow and terrain and make terrain decisions.
Francois introduced us to the "Ne-bo test" or Nivo-test - a pocket tool
for avalanche risk estimation created by R. Bolognesi (this test is area
specific, or only works in a given area)
Not available in Canada. For more information: www.meteorisk.ca or
*benefits - it is self sufficient, designed to help beginners, cheap, and
gives a rule-based risk evaluation. (it will be interesting if this should
surface in Canada one day....)
Director of the Gallatin National Forest
Avalanche Center in Montana
Doug received his B.A. in Outdoor Education from
Prescott College in 1986 and has worked as a professional mountain guide in
Alaska and the western US from 1989 to present. He is a senior guide at Exum
Mountain Guides in the Tetons and has been on many climbing expeditions in
Alaska, Nepal, India and Pakistan. Doug now snowmobiles over 1,200 off-trail
miles a year on his Polaris 800 RMK, and spends much of his time figuring
out ways to make snowmobiling safer in avalanche terrain.
TOPIC: Doug will discuss ways to identify avalanche
terrain, talk about how weather affects stability, give sledders tools to
answer the question, "Can the snow slide?", discuss riding techniques that
can minimize our risk, and explore snowmobile avalanche accident cases and
discuss the factors that led up to it.
Rescue times and survival statistics "the reality"
- Rescue in the first 15min (possible if buried in snow 3ft from the
surface of less) survival rate 90%
- Rescue in the first 30min = 50%
Rescues and Body recoveries a study:
These percentages were based on burial survivals and recoveries and the
methods or rescue in each situation.
||Organized (SAR) rescue
*indicating that your survival when buried is reliant on your companions
ability to find and uncover you in the first 15-30 min.*
Rescue doesn't work well. Proper Evaluation is the key to survival!
- Look for avalanche indicators (ie: extensive tree damage, evidence of
- Stay away from Gullies or terrain traps that offer no escape options.
Even small slopes (terrain traps) can slide with devastating effect.
- Watch out for rapid snow loading
- Rain adds heaviness or weight to the snow pack.
- Wind = loading (look for wind texturing, loading, plumes *or blowing
snow off of peaks above you* wind slabs)
Dr. Dave McClung
University of British Columbia, NSERC Chair
in Snow and Avalanche Science
TOPIC: In his presentation, Avalanche Forecasting
in the Backcountry: The Avalanche Enigma? Dr. McClung will explain the
latest thinking on snow slab instability (e.g. fracture toughness) and what
it means to the backcountry skier, boarder or sledder in relation to
forecasting in the backcountry. At stake is the relevance of the snow pack
measurements we use to help evaluate the situation to help with decisions.
Avalanche Forecasting Predication is based upon many variables:
- a size 2 avalanche is big enough to bury, injure or kill a skier.
Relevant to a given triggering level ie: a snowmobile can trigger deeper
fractures that a skis might not.
- Spatial and temporal variability of the snow cover. (block test)
- Incremental changes in snow and weather
- Human Factors: or variations in human perceptions
The Public Bulletin (PAB) must be supplemented by field observations. (microscale)
*Considerable is an ambiguous term it adds to poor perception.
Considerable + field obs!
(potential problem - signs of instability may not be visible or readily
Dave "plugged" or advocated Munter's Reduction method. He likes it
because it helps with human biases and it is simple to understand and apply.
10-20 cm of snowfall can be propagation for a weak layer which results in
Toughness Depends on:
- Shear strength
- Slab stiffness
- Interaction of imperfections on a Macroscopic level
- 10's of cm are important (depth of new snowfall)
- Rate of snow pack failure (block test)
- Temperature variations
- Weak layers (facets, surface hoar etc) These can be very difficult to
determine even for experts.
*Cannot accurately measure an avalanche risk before it releases*
That makes avalanche danger calculations "Probablalistic" or based on
risk evaluation. Most deaths occur because of a failure in human perception.
Avalanche risk can be managed in terms of probabilities but not eliminated.
(eg. appropriate terrain selection for the conditions, this is where human
factors play a key role in risk management.)
UBC Snow Science Researcher
A 30-year-old Icelander, has been in Canada since
2001 to work on her thesis on Avalanche Risk Management in Backcountry
Skiing Operations at UBC. She grew up in Neskaupstaður, a small town on the
east coast of Iceland, surrounded by steep mountains and the ocean and
worked in the avalanche department of the Icelandic Meteorological Office
for three years before coming to Canada. Her main focus was on avalanche
hazard mapping for villages.
TOPIC: Avalanche risk management during backcountry
travelling - Analysis of risk factors in terms of terrain. Harpa will show
some results from historical data collected from Canadian Mountain Holidays,
including patterns in aspect, snow stability rating, elevation level and
time of the year. She will also discuss findings from interviews with
professional guides. Results from this research will be compared existing
decision making methods, such as Munter’s Reduction Method.
Data on usage of terrain and risk analysis (*definitions)
Time of year:
- Early Dec. 1st to Jan 31st
- Mid Feb. 1st to March 15th
- Late March 16th to April 30th
- Alpine: 2200m
- Tree line: 1800 - 2200m
- Sub Tree: below 1800m
Aspects of highest risk:
- Mid season tends to be peak risk.
Seasonal aspect usage studied: (Based on usage by Professional heli-skiing
- Early Winter: Southern Aspects are used more often
- Late Season: Northern Aspects more frequently used (solar radiation on
the snow creating a weaker snow pack on southern aspects in late season.)
- Risk tends to be lower in the SW W and NW aspects
- Risk is highest mid season and lowest in late season
- Inclination is important on a smaller scale (ie: field obs on
Ranking factors in Terrain Selection:
- General shape of terrain - are there any "big terrain features"
- inclination - constant idea of slope features and angles above 30deg
- Avalanche history of terrain, what has already slid, and what will
- Places prone to the development of surface hoar
- Aspect selection is important.
Watch out for:
- Convex Rolls (unsupported features)
- Cutbacks - these grow surface hoar and lack anchoring ability
- Glades, tree shoots, wind loaded pockets, gullies
- Shallow snow pack (*warning it takes experience over specific terrain
in varying conditions to know where the snow pack is shallow)
- Be conservative in the beginning
- Sharing information is important! discuss the history of the snow pack
with the locals
- Learn to recognise problem spots
- Rule based go no-go procedures = smaller amount of room for human
- Experience and good judgement is always the best combination for
Mountain Guide, International Federation of
Mountain Guide Associations (IFMGA)
Based in Vancouver, Lars is a Kinesiology graduate
of the U of C, who has worked as a professional mountain guide for seven
years and who has guided for ski touring and mechanized ski operations for a
total of ten. Lars has extensive ski touring experience in all ranges of BC,
Alberta and Alaska, most notably the Coast Range and the Columbia Mountains.
He has been involved in numerous expeditions to Alaska, in the St Elias
Mountains and Kluane Park.
TOPIC: Terrain choices for ski touring.
On Mountain terrain or critical terrain features:
- Terrain choice is the critical element to accident avoidance.
Identifying potential risky terrain components , learning terrain, is key.
Apply the CAA bulletin to your terrain choice.
- Winter Terrain = mountain geography + snow pack
- We (commercial guides) manage avalanche risk through terrain selection
and snow pack and our degree of confidence in that selection. Daily group
meetings are held and the group evaluates the information on hand.
(Bulletins, weather repts, topo map, shared field obs) and makes a
decision together. The final decision always defaults to the comfort level
of the "least comfortable person" (ie: 4 think it's okay and one
disagrees, it's a no go!) In times of snow pack uncertainty ie- no report,
bulletin or field obs available, we resort to terrain selection.
Things to consider when selecting terrain:
- Shape and size of terrain, unique and identifying terrain, identify
and mark areas of concern, understand the "why" and the "where" when
- *Slope size and shape, convexity or degree of slope, big terrain (how
much snow will potentially fall) what is your exposure to surrounding
terrain. (avoid travel below big terrain features), terrain traps
(gullies) is the area prone to surface hoar?
- What is the Elevation are you travelling within? Alpine, tree line, or
- What are the chances of surface hoar instability?
- What aspects will you choose, have you considered wind loading
patterns, or solar radiation exposure on the snow pack. All terrain
selection decisions are also based on seasonal snow pack conditions and
knowledge of unusual loading in specific terrain features. (This is where
experience in the terrain is key!)