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A group of students on an avalanche-training course with the Whistler Alpine Guides Bureau ski out of an unpatrolled area on Tuesday. (John Lehmann/The Globe and Mail)
A group of students on an avalanche-training course with the Whistler Alpine Guides Bureau ski out of an unpatrolled area on Tuesday. (John Lehmann/The Globe and Mail)


Students’ deaths transformed Canada’s attitude towards avalanches Add to ...

Karl Klassen, the centre’s acting executive director, said during his 35 years in the backcountry industry he has noticed the number of recreationalists going up, but the number of deadly incidents not rising in tandem.

“That gives me hope that we’ve been able to help people understand the problem,” he said.

Avalanche Terrain Exposure Scale

Mountain guides have always recognized that landscape is as important as snow and weather conditions in assessing avalanche risk, but Parks Canada went a step further and created a formal system to rate terrain for the public using a three-tier scale.

The Avalanche Terrain Exposure Scale, dubbed ATES and implemented in 2004, catalogues about 300 trails in the national parks as either Class 1 “simple,” Class 2 “challenging” or Class 3 “complex.”

Simple terrain includes trails at low angles, through forests and far from avalanche paths or glaciers. Challenging terrain features straightforward travel on glaciers, some crevasse hazards as well as exposure to well-defined avalanche paths, but with routes to avoid them. Complex terrain involves complicated glacier travel, exposure to multiple overlapping slide paths, steep terrain and few escape routes.

Where does the Connaught Creek trail rank?

“It’s our poster child for complex terrain,” said Mr. Statham of Parks Canada. “It’s a very narrow valley with a lot of avalanche paths hanging over your head. It’s difficult to predict anything because the area where the avalanche starts is 1,000 metres above your head.”

A surge in snowmobile deaths in the winter of 2008-09 sparked renewed interest in avalanche safety. A total of 26 people would die that season; 19 were snowmobilers in B.C. The avalanche centre is now halfway through a four-year project to map all of B.C.’s 91 provincially managed snowmobile routes using ATES, and has already completed 59, or about 4,000 square kilometres.

ATES has been embraced by other alpine nations, including the United States, Italy, Norway, Japan and New Zealand.

Custodial Groups

In 2004, Parks Canada introduced risk-management rules related to minors travelling in the mountains without their parents or legal guardians, but with institutions such as schools, community groups, Scouts and Guides. The rules don’t apply to groups of friends or families.

“When we first started, there was lots of fear, particularly in the outdoor-education sector,” Mr. Statham said.

He said the Arato family was instrumental in advocating for rules for custodial groups.

“It was a recognition that the whole process was broken,” Mr. Arato said. “What may be suitable or appropriate for adults that have made their own choices and understand their own risk – that does not apply to custodial group.”

Tied to ATES, unguided custodial groups are kept to low-risk Class 1 places, but should avoid them when avalanche advisories are “poor”; in Class 2 terrain they must hire licensed mountain guides, keep the group size to 10 and have snow stability on that slope rated “good” or “very good”; they are banned in Class 3 high-risk areas altogether.

The system also serves as a good guide for families or novice outdoor enthusiasts looking for the least risky trails to tackle. Other countries have adopted the system, too.

“I thought that was wonderful because it makes you feel that you’ve been able to make a difference,” Ms. Arato said.

North American Public Avalanche Danger Scale

Experts began working on easy-to-understand avalanche bulletins for the public and released a first set of simple icons in 2004. The system was quickly adopted in Switzerland and, with further tinkering, became the European standard. Revisions continued and, in 2010, Parks Canada, the avalanche centre and other collaborators unveiled the North American Public Avalanche Danger Scale, which uses colourful images and ranks the danger level – low, moderate, considerable, high and extreme. The scale rates the likelihood of a slide – unlikely to certain. It also rates the size and distribution – small in isolated areas of extreme terrain to very large avalanches in many places. The scale also provides advice in plain language such as travel is considered “generally safe” to “very dangerous avalanche conditions” to “avoid all avalanche terrain.”

Last year, Parks Canada and the avalanche centre, with the help of the Alberta government, released AvalX, a new standardized format for public avalanche bulletins based on the revised North American danger scale, which uses more graphics, less text and is smartphone friendly. Further improvements were made in time for this winter.

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