VANCOUVER — The race against the clock that begins when a person is buried by an avalanche is a tighter race than it was believed, says a newly published study that found avalanche victims have a shorter window for rescue in the Canadian backcountry than on European slopes.
The study, published Monday in the Canadian Medical Association Journal, suggests current avalanche safety guidelines in this country — which are based on Swiss practises — may need to be updated to reflect the distinct danger faced by people swallowed by slow slides in Canada.
Researcher Pascal Haegeli of Simon Fraser University examined avalanche statistics in both Canada and Switzerland between 1980 and 2005, and he found important differences.
The survival rates themselves were about the same at 47 per cent, but victims in Canadian avalanches died sooner.
Haegeli found people who were completely buried in Swiss avalanches had survival rates of 94 per cent if they were recovered in the first 10 minutes, and 71 per cent if they were recovered between 11 and 20 minutes after they were buried.
In contrast, the 10-minute survival rate in Canada was slightly lower at 90 per cent, but dramatically less after that. Victims who were buried in an avalanche in Canada who were rescued between 11 and 20 minutes after they were buried had a survival rate of just 36 per cent.
“At all burial durations, the chances of surviving a full burial in Canada are a lot worse,” Haegeli said in an interview from Swizerland, where he is currently travelling.
The overall survival rates were comparable, said Haegeli, because Canadian victims are generally rescued faster by their companions.
Haegeli said there are several factors that can explain the differences.
People who find themselves in the Canadian backcountry are generally in areas with more trees, making it far more likely they will die of trauma injuries during the avalanche itself.
If they survive the avalanche, they are buried under denser snow, which means they have a higher chance of suffocating.
And even if they are rescued, particularly after an extended period of time under the snow, Canadian victims are typically in more remote locations, where on-site medical care is less common and where the distance to medical facilities is farther.
“It clearly highlights that efficient companion rescue is clearly the key — the quicker you can dig somebody out, the higher the chances of survival,” he said.
The current guideline of 18 minutes is based on the Swiss experience.
“Based on our study, we think that 10 minutes would be a more appropriate guideline for Canadian standards,” he said.
Haegeli’s paper also says rescue teams must be educated in avalanche resuscitation techniques and search-and-rescue protocols need to ensure more efficient evacuation to medical treatment.
The B.C.-based Canadian Avalanche Centre, which provided the Canadian data for Haegeli’s study, welcomed the results and would consider whether it can use the research to improve its own safety programs.
Spokesman John Kelly said the centre currently teaches the importance of rescuing an avalanche victim within 15 minutes, but he added the real lesson is that people buried in the snow need to be uncovered as soon as possible.
“It (the study) really underlines what we already did know, that companion rescue is an incredibly critical thing, you must be rescued on the spot by your companion to have a good chance of survival,” Kelly said in an interview.
“The objective is for quicker rescue. Four minutes is better than five minutes, is better than eight minutes. There’s no goalpost in this.”
Kelly said the centre is already well aware of the limitations when it comes to offering medical treatment in the backcountry. He said the organization is always working to update its policies to address those concerns.
Despite dire warnings over several weeks earlier this year about especially treacherous conditions, Kelly said the season has so far been relatively average, both in terms of overall conditions and fatalities.
So far 11 people have died in Canadian avalanches, most in B.C.
Last year, 12 people died in 10 avalanches. In 2008-2009, there were 26 fatalities in 17 avalanches — including eight men who were killed in a single avalanche near Fernie, B.C.
“It’s been a pretty average year, and I say that with a sense of relief because we’ve come through three very unusual and nerve-wracking years,” said Kelly.