5 people were killed in B.C.’s backcountry this year. Experts say this deadly season started months ago
Five people have been killed in avalanches across B.C. in the past month, including experienced skiiers and brothers on a guided heli-skiing trip in B.C.’s Interior.
Forecasters have compared this season’s snowpack with conditions seen two decades ago, during one of the province’s worst years on record for avalanches fatalities.
Experts have an explanation for what’s making this season so deadly — and they say it started months ago.
How dangerous are avalanche conditions in B.C. right now?
This year’s snowpack, with a weak layer of sugar-like crystals buried near the bottom, is being described as similar to that of 2003, when avalanches in Western Canada killed 29 people. Most of them were in B.C.
Avalanche Canada said conditions are particularly dangerous throughout the Interior, but more typical on B.C.’s South Coast.
What do experts mean when they talk about snowpack?
Snow that falls onto the ground and does not melt until warmer temperatures in the spring is called snowpack. Snowpack can consist of multiple layers of snow, each one from a different snowfall, that become compacted — or pressed firmly together — under the weight of the layers falling on top.
A weak snowpack happens when one of the middle layers doesn’t bond well to those around it. This fragile layer can collapse under the weight of topside snow and slip away. This leads to a slide called a slab avalanche.
This year’s snowpack has a one major weak layer closer to the base and various other bad layers too.
What caused this weak snowpack?
A large part of B.C.’s problem this year began in the fall.
A shallow amount of snow near the ground was frozen by long spells of Arctic air in November and December.
When a thin snowpack is exposed to cold temperatures for a long period of time, snow grains get bigger and sharper. That means less overall surface area, which means fewer spots for the crystal-like snow to bond with layers of powder on top.
It’s left the B.C. Interior with a weak foundation holding up the rest of the deep snowpack.
“It’s just a perfect combination of things to build a weak base,” said Ryan Buhler, Avalanche Canada’s forecast program supervisor.
How can you tell when a snowpack is weak or unstable?
There are multiple warning signs a snowpack isn’t stable, though clues aren’t popping up as often this year because the weak layer is so deep.
“It is catching people by surprise,” Buhler said.
If you see cracks shooting across the snow under your weight, signs of a recent avalanche or hear a sound known as a “whumpf” — these are all signals the snowpack might not be safe.
A “whumpf” is the noise of snow falling into itself when a weak layer collapses. It sounds exactly like the word.
WATCH | This is what cracks can look like:
How long will conditions in B.C. last?
Pascal Haegeli, an avalanche safety researcher at Simon Fraser University in Burnaby, B.C., said he expects the weakness in the snowpack to be around for the rest of the season because the problematic layer is buried so deeply.
It would take weeks of consistently warm temperatures to reach down far enough to melt it, which Haegeli said isn’t likely until spring.
Where can avalanches happen?
Anywhere where the hill is steep enough. Most slides happen on inclines with an angle between 35 and 45 degrees, which is about as steep as double black diamond ski run, but they can happen elsewhere too.
Once a slope is larger than a tennis court — about 10 square metres — it could have enough snow for an avalanche.
What can I do to stay safe?
Check the avalanche forecast and make conservative decisions about which terrain you choose to explore. An avalanche transceiver, snow probe and snow shovel are essential, but you shouldn’t just throw them in your pack — make sure you’ve practised and know how to use them.
Even professionals are being cautious this season, Buhler warned.
“Now is not a time to push out and go for big objectives. Realistically, it may be that message for the entire season … it may just be a season to back off,” he said.
“There will be places where things are stable, but we just can’t pinpoint those right now. So the overall message is be patient and be conservative.”
Experts say climate change has led to more rapid change in the backcountry, so a user’s previous experience might be outdated.
“The trip that you might have done 10 years ago, you might just have to think about it twice before committing to a trip based on the current conditions,” said Haegeli, the researcher from SFU.
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What is an avalanche forecast?
The avalanche forecast tells the public how likely avalanches might be on a certain day in a certain area, based on the snowpack and the weather forecast. The forecast should be the first place to look before a trip.
What are the different danger ratings?
According to Avalanche Canada, the ratings are as follows:
- 5 — Extreme: Extraordinarily dangerous avalanche conditions where natural and human-triggered slides are a certainty. People should avoid all avalanche terrain.
- 4 — High: Very dangerous conditions where human-triggered avalanches are “very likely.” Travel is not recommended.
- 3 — Considerable: Dangerous conditions where human-triggered avalanches are “likely.” People should make careful decisions and avoid extra risk.
- 2 — Moderate: Heightened avalanche conditions on specific terrain features where human-triggered avalanches are “possible.”
- 1 — Low: Generally safe avalanche conditions where slides are “unlikely.”
A timeline of avalanche events this season
Dec. 31: A skier suffers life-threatening injuries in a slide near Emerald Lake in southeast B.C., near the Alberta border, Avalanche Canada says in a report.
Jan. 5: Avalanche Canada warns of a touchy snowpack, with various weak layers created by long periods of drought and cold weather.
“Riders have triggered large, scary avalanches with high consequences,” the advisory says.
Jan. 9: Two off-duty police officers are caught up in an avalanche near Kaslo, B.C., while backcountry skiing. Nelson Police Service Const. Wade Tittemore, 43, dies and Const. Mathieu Nolet, 28, sustains severe internal injuries.
Jan. 21: Nolet dies of his injuries in hospital.
Jan. 21: Two snowmobilers riding at the base of a slope near Valemount, B.C., accidentally trigger an avalanche from above, sending a slab of snow onto one rider while the other escapes. The buried rider is found unresponsive and dies.
Jan. 23: Heli-skiers and their guide are caught in an avalanche near Revelstoke, B.C. The two guests, brothers and American businessmen Jon and Tim Kinsley, are dug out of the snow unresponsive and are both declared dead in hospital. The guide is taken to hospital in stable condition.
Jan. 23: A slide comes down on one person near Cherryville, B.C. Emergency health services says the person is taken to hospital with undetermined injuries.
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