TORONTO (OHS Canada)
Thousands of tonnes of snow charging down a mountain, mowing down everything in its path, is an ever-present threat to backcountry skiers, snowmobilers, hikers and thrill-seekers who use mountains for fun.
But what about those who use mountains for work? Or for rescuing thrill-seekers whose days have gone terribly wrong?
Forestry workers, miners, park rangers and rescue crews may also face an avalanche’s unleashing fury, at risk of being swept away and buried deep in a tidal wave of snow.
The worst avalanche tragedy in Canadian history was in 1910, when 62 Canadian Pacific Railway workers were buried while clearing snow from a previous slide off the railroad tracks in Rogers Pass, British Columbia.
Today, avalanches claim an average of 14 Canadians every year. In late December, the RCMP confirmed a 45-year-old man had died while heli-skiing in the Selkirk Mountain range in British Columbia. At about 1:35 pm on December 30, a certified guide and 11 skiers were skiing when the avalanche, categorized as size 2.5 on a five-point scale, occurred. Three skiers were partially buried and rescued uninjured; a fourth skier was completely buried and later pronounced dead.
Those who work in the mountain ranges on Canada’s West Coast are – for obvious reasons – most at risk from avalanches, but any terrain with steep inclines and snowfalls can produce potentially deadly slides.
“There are avalanche fatalities recorded in most provinces in Canada, even though not all provinces have mountains,” says Ian Tomm, executive director of the Canadian Avalanche Association (CAA) in Revelstoke, British Columbia. “There have been fatalities in Quebec that have happened on tailings. These big piles of rocks from the mines are steep enough – over 30 degrees slope angle – and if the winter storms are depositing enough snow on it, it can create an avalanche hazard,” Tomm reports.
The rule of thumb for avalanche risk is more than 30 centimetres of snowfall, greater than 30 degrees of slope and wind speeds exceeding 30 kilometres per hour, he says.
In British Columbia, before any work is done during wintertime, an avalanche risk assessment must be carried out. If any risk is identified, a written avalanche safety plan must be developed and submitted to WorkSafeBC.
“Are you going to do avalanche control through bombing or, once you hit higher levels of risk, will you shut the roads down and move out of the area?” Bruce Clarke, the Prince George regional prevention manager for WorkSafeBC, says as an example. “We recognize in a lot of cases you can’t eliminate the risk, but what our regulations expect is, as an employer, if your workers are in danger, you’re going to mitigate those risks to the lowest level possible.”
The avalanche safety plan would likely require availability of rescue and recovery equipment such as transponders, probes, shovels and inflatable snow vests, Clarke says.
For WorkSafeBC staff, those who go into the backcountry must complete an eight-day training course on avalanches and always work in pairs. “If an individual gets buried, that other individual who is with them can’t put themselves in a situation where they’re at risk at the same time. But if they have to initiate a rescue, they can identify if there are any more risks to themselves,” Clarke says.
Following an avalanche, there is an increased risk of another slide unless most of the snow shelf above has come down. If rescuer safety cannot be guaranteed, Tomm says there have been numerous cases where search and rescue “efforts have been suspended and avalanche experts have been brought in to do more in-depth analysis and explosive control.”
Fortunately, the CAA reports that incidents involving Canadian workers being injured or killed by avalanches are declining. The last worker fatality occurred in January, 2006 when an employee of Island Lake Lodge in Fernie, British Columbia was caught while checking a weather station. A size 3.5 avalanche – typically 1,000 tonnes and running about a kilometre – exceeded its normal run and the employee was buried in the 300-metre wide, two-and-a-half metre thick slab.
WorkSafeBC reports that there were 11 avalanche-related claims from 2006 to 2010. One fatality and four injuries involved workers in the outdoor sport tour industry.
Tomm says that the low number of injuries speaks to the high standards of training and certification for avalanche risk management workers, increased understanding of the science behind avalanches and the tools to predict them, and the size of the industry in Canada. There are currently approximately 500 to 600 people in Canada whose full-time winter employment revolves around managing and controlling avalanche hazards.
“We’ve got this massive industry, it’s the largest in the world, that creates a rich environment of colleague-to-colleague information sharing and it’s very open in this industry,” Tomm says. “Collectively that’s really improved the levels of safety and standards that are out there.”
For more information, check out these links:
Canadian Avalanche Centre
Avalanche Size Classification
Major Avalanches in Canada
Parks Canada Avalanche Awareness Initiatives