[ Rescue Dynamics Logo ] Outdoor Article of the Month - October 1999

Snow Safety and Avalanches
A Heli-ski Primer

© 1999 Cyril Shokoples

Avalanches are a fact of life when skiing in the mountains. Because of this, heli-ski operators and guides work exhaustively at reducing the risk and reducing exposure to avalanche hazard. There are many ways in which safety is enhanced . This page will describe a few of these important measures.



[ ACMG logo ][ UIAGM logo ]The first line of defense when working in avalanche terrain is hiring trained professional mountain guides who have appropriate skills and qualifications to work in mountain terrain in the winter. Lead guides are often internationally certified as full mountain guides through the UIAGM / IFMGA (International Federation of Mountain Guides Associations). They are often full members of the Association of Canadian Mountain Guides (ACMG) and professional members of the Canadian Avalanche Association. To meet the exacting standards prescribed by these associations requires years of practical experience and completion of numerous courses and examinations. In order to maintain their professional status, each guide is required to continually maintain and upgrade their skills. Most guides are required to be members of the ACMG at either the Full Mountain Guide, Ski Guide or Assistant Ski Guide level. As part of their professional qualification, each guide is also required to hold, at minimum, an advanced first aid certification. Some guides hold additional qualifications in many other diverse and related fields, including explosive control, mountain rescue and emergency medical areas.

Avalanche professionals describe the three most important things in avalanche safety as terrain, terrain, terrain. This means that selection of the appropriate terrain on any given day is one of the best ways of avoiding avalanche involvements. Trained professional guides have the skills required to make the all important terrain decisions.

Industry Standards

Most heli-ski operators are members of the British Columbia Heli-ski and Snowcat Operators Association, and as such are required to conform to certain industry standards and practices. In order to meet or exceed these standards they are subject to periodic inspections by the association to ensure that they continue to do so. In addition to these inspections, operators also occasionally hire independent consultants to provide expert opinions on how they can continue to enhance their avalanche and snow safety programs. Many of Canada's most prominent experts visit ski operations with this aim in mind.

CAA Infoex

As part of their snow safety program, most operators subscribe to the Canadian Avalanche Association Information Exchange (CAA Infoex). This is an unprecedented cooperative effort involving all of the leading operations involved in avalanche safety in Western Canada. Every day throughout the winter as many as one hundred parks, ski areas, snowcat, heli-ski, and government avalanche safety programs report their daily weather, snowpack and avalanche observations along with their stability evaluation to a central location in Revelstoke, British Columbia. This large pool of data is reported using a special shorthand developed for relaying a vast amount of information with a minimal amount of effort. This data is compiled each night and then returned via the Internet to each member agency. The value of this exchange is that you can evaluate what the vast majority of avalanche experts are seeing and reporting regarding all of the factors relevant to avalanche stability. Particular attention is paid to operations which are nearby or experiencing similar snowpack characteristics. This is a valuable tool in assessing trends in snow stability that may be common to certain regions.

Weather Forecast

Persons familiar with the avalanche phenomenon are fond of saying that there are three major precursors to avalanche activity; precipitation (snow / rain), wind and temperature. Since these are all weather related factors, it is vital to have a very detailed mountain weather forecast. Most operators subscribe to a special mountain weather forecast produced for ski operations by the Mountain Weather Office of Environment Canada in Kelowna. (It is a confidential forecast and cannot be released to the public.) This forecast is received via the internet at 07:00 each morning and contains the following:

In addition, guides often look at visible, IR, animated and composite satellite imagery on the internet. This weather information is discussed each morning at the guides meeting as part of the avalanche forecasting process. It also is discussed as it relates to flying considerations. The important weather factors are written into a daily log and also written on a large board each morning. Using information from the forecast, a weather map is also often drawn.

Season Profile ChartSeason Profile

On the wall of the Guide's office in most major operations is a very large chart on which a large number of variables are plotted on a daily basis. On the top of the chart is the morning cloud cover. Just below it is coded the rate of morning precipitation. The 24 hour high, low and current temperature are drawn in graphical form. The actual winds at 10,000 feet / 3000m at Kelowna are then plotted. Below that, the previous day's avalanche stability rating is noted. The frequency, type and size of avalanches are noted in graphical form as well. Further down on the chart the height of snow at each of the four snow study sites visited is charted. At the bottom of the profile chart the height of new snow at each of the study sites visited is noted.

Field Observations

During the day, heli-ski guests often see their guide recording information in a notebook. As trained professional observers, guides are constantly recording wind, temperatures, snowpack data, avalanche observations and results of any tests. This information is then compiled later in the day in formulating a stability analysis. Any significant observations made are often immediately reported by radio to other guides in the field.

The observation of type and size of natural avalanche events is particularly important as an indicator of stability and extent of risk on any given day. Avalanches are classed according to type (loose or slab / wet or dry, etc.) and size. The smallest avalanches are classed as size 1 (not big enough to bury a person) while the largest are classed as size 5 (the largest destructive avalanches known).

Study Plots and Snow Profiles

Most operations maintain snow study site locations in various geographic areas within their heli-ski terrain. Each of these study sites has a stake for recording the height of accumulated settled snow as well as a second stake for recording the height of new or storm snow. This information is recorded on the Season Profile.

Once every two weeks a "Full Snow Profile" is usually done at a specially selected standardized snow study plot. A guide will dig down to the ground (as much as 3m or 10 feet) and analyze all of the layers in the snowpack. Observations made while doing this "Snow Pit" or snow profile include:

This information is then graphed using a computer program and displayed on a board in the guide's office. This full profile is used as a baseline for tracking changes in the snowpack.

Many other "test" profiles are done as needed to provide more timely information or to provide information about a specific geographic area or when tracking changes in a layer of particular interest.

Any critical layers that are noted in the snowpack are recorded on a special board in the guide's office and are tracked continually as the season progresses. This is an ongoing process, as one layer may begin to strengthen and bond while another layer weakens or perhaps a new layer is formed. Snow is never static and a variety of processes within the snowpack compete to change or "metamorphose" the snow crystals in different ways.

Snow PitField Tests

During your ski day you may notice your guide is always poking and prodding the snow and may actually take out a shovel to dig a hole or pit in the snow. Your guide is not nervous or crazy, they are simply constantly monitoring the snowpack for changes. It is amazing what a trained professional can determine by the use of very simple tests. The key is really constant testing. Some of the tests used include the shovel shear test, compression test, Rutschblock test, hand shear test, ski pole test, probing, ski cutting and test snow profiles.

Should your guide stop and ask you to wait while they conduct a test or dig a pit, please be patient. It is all in the interest of your safety! If you are interested in the nature of the tests being conducted, ask your guide to provide a simple explanation or demonstration. They are usually all too happy to enhance the knowledge of others in regard to snow safety.

Explosive testing and control

On rare occasions it is felt necessary to use explosives as an attempt to control avalanche slopes that may threaten runs. Explosives can be used as a means of stabilization and control of selected slopes or they can be used as a test of snow stability in general. Explosives are never used indiscriminately. As a rule, explosive work is only effective if you use the right charge, on the right place on a slope, at the right time. Otherwise the use of explosives can be a costly way to make a loud nose and produce a dark hole in the snow without creating an avalanche.

Over time operations develop a very good catalog of indicator slopes that can be effectively tested or stabilized with explosives. Even explosive control cannot eliminate the risk of avalanches on any given slope.

Morning Guides Meeting

Each morning at about 07:00 the daily activities for the guides begins. One person goes to a weather plot to make the morning weather and snow observations. Often the guide then logs onto the internet and downloads the CAA Infoex and the Morning Weather. The relevant observations are plotted on the season profile and recorded in the daily log. The guides and pilots read the morning weather, CAA Infoex and plot the weather map in preparation for the business of the meeting.

Typically, around 07:30 the meeting begins in earnest. Snow stability, weather, avalanche and flying considerations are discussed. All of the considerations mentioned above may enter into the forecast of today's snow stability. Based on the new snow stability forecast and the weather forecast a run list is prepared for the day. A sheet containing a list of all (or most) of the different runs is color coded red, yellow or green. A run is coded green if it is considered safe to ski on that day. A run is coded red if it is considered unsafe to ski on that day. (Once coded red, there is no way to change the coding of the run until the next day. It cannot be skied that day!) A run is coded yellow if further observation is required to make a valid determination. A yellow run can only be skied if the guides in the field make a unanimous decision that it can now be considered green. Any guide has the power of veto and can change the code of a yellow run to red, either in the office or in the field.

An operational plan for the day is then determined and one or more alternate plans may be considered as well in case of changes in weather, etc. By 08:00 the meeting is over and the guides have breakfast. Shortly after the guides change into their ski clothes and prepare to meet the guests. Later in the morning the safety briefings begin. Once the briefings are completed, the first group flies away and the day's heli-ski program is in motion.

Evening Guides Meeting

When the heli-skiers arrive back at the Heliplex, often all they can think of is relaxing, having a drink or two and perhaps a few snacks from the restaurant while they laugh and reflect on the events of the day. For the guides and pilots the day is not yet over. As the saying goes, "The job is not done until the paperwork is completed." After socializing for a short time with the heli-skiers, the guides and pilots get together again for the evening guides meeting. The overall success of the day is discussed with an eye toward constantly improving the quality of service provided to their guests. The pilots present any special concerns they may have had in regard to the flying or related issues. The weather, avalanche, and snowpack observations are recorded in the daily log and plotted on the seasons profile if necessary. Any snow profiles are entered into the computer and a graph is printed. The snowpack structure is discussed and recorded in the daily log. A decision is made regarding the snow stability and a rating (from very poor to very good) is made for each of three elevation regimes; Alpine, Treeline and Below Treeline.

The daily statistics are entered into the computer. Finally, a standard form is completed with our weather, snowpack, avalanche activity and stability analysis and sent via email to the CAA Infoex in Revelstoke. With this being done, the guides can finally relax. The following morning, the cycle of activity begins again!

A Few Final Thoughts

Even with all of the mitigating efforts outlined above and many more, the possibility of avalanches always exists to some degree when heli-skiing. Is is impossible to control nature or the weather. The risk of avalanche is something you must acknowledge and accept if you are to go heli-skiing. Guides accept this risk on a daily basis throughout the winter, but only you can decide if the risk is acceptable to you.

If you are curious about any of the items mentioned above, be sure to ask you guide to provide you with further details... and have a great time!

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Last updated Saturday, April 26, 2014