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5 people were killed in B.C.’s backcountry this year. Experts say this deadly season started months ago

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Five people have been killed in avalanches across B.C. in the past month,┬аincluding 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,┬аduring one of the province’s worst years on record for avalanches fatalities.

Experts have an explanation for what’s making this season so deadly┬атАФ 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┬аmore typical on B.C.’s South Coast.

What do experts mean when they talk about snowpack?

Snow that falls onto the ground and┬аdoes not melt until warmer┬аtemperatures┬аin the spring is called snowpack. Snowpack can consist of multiple layers of snow, each one from a different snowfall, that become compacted┬атАФ or pressed firmly together┬атАФ┬аunder the weight of the┬аlayers falling┬аon top.

A weak snowpack happens when one of the┬аmiddle┬аlayers doesn’t bond well to those around it. This┬аfragile layer┬аcan collapse under the weight of topside snow and slip away. This┬аleads┬аto a slide called a┬аslab avalanche.

This year’s snowpack has a one major weak layer closer to the base and various other bad┬аlayers too.

On Jan. 30, 2016, a vehicle passes a sign showing an avalanche hazard warning of ‘considerable’ at a parking lot where snowmobilers embark from near Mount Renshaw outside of McBride, B.C. Five snowmobilers died the previous day in a major avalanche in the Renshaw area east of McBride. (Darryl Dyck/The Canadian Press)

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┬аof 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┬аthe B.C. Interior┬аwith a weak foundation holding up the rest of the deep snowpack.

“It’s just a┬аperfect combination of things to build a weak base,” said┬аRyan Buhler, Avalanche Canada’s┬аforecast 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,”┬аBuhler 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”┬атАФ 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┬аis buried so deeply.

It would take weeks of consistently warm┬аtemperatures to reach down far enough to melt it,┬аwhich Haegeli said┬аisn’t likely until spring.

Where can avalanches happen?

Anywhere where the hill is steep enough. Most slides happen on inclines┬аwith┬аan angle between 35 and 45 degrees,┬аwhich 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┬атАФ about 10 square metres┬атАФ┬аit 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┬атАФ make sure you’ve practised and know how to use them.

Even professionals┬аare being cautious this season, Buhler┬аwarned.

“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.”

A map shows avalanche risk in the province is low on B.C.'s south coast, moderate to high in the Interior, and moderate to high on B.C.'s northwest coast.
Avalanche Canada danger map pictured on Monday. Yellow denotes heightened risk, orange denotes dangerous and red means very dangerous conditions. (Avalanche Canada)

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┬аHaegeli, the researcher from SFU.

LISTEN | Experts weigh in on unpredictable avalanche conditions

BC Today51:34Interest rate impacts on house prices; Unpredictable backcountry season

The Bank of Canada raises its key interest rate again тАФ but hints that may be it, as the economy starts to slow down, in particular, in the housing market. We’re asking: Have you held off on a big purchase like a home? And, it’s a tragic season in BC’s backcountry. Two more people have died in an avalanche near Revelstoke. Are there now new and unpredictable risks in the mountains?

What is an avalanche forecast?

The┬аavalanche forecast┬аtells the public┬аhow likely avalanches might be on a certain day in a┬аcertain area, based on the snowpack and the weather forecast. The forecast should be┬аthe first place to look before a┬аtrip.

What are the different danger ratings?

According to Avalanche Canada, the ratings are as follows:

  • 5 тАФ Extreme: Extraordinarily dangerous avalanche conditions where natural and human-triggered slides are a certainty. People should avoid all avalanche terrain.
  • 4 тАФ High:┬аVery dangerous conditions where human-triggered avalanches are “very likely.” Travel is not recommended.
  • 3 тАФ Considerable: Dangerous┬аconditions where human-triggered avalanches are “likely.” People should make careful decisions and avoid extra risk.
  • 2 тАФ┬а Moderate: Heightened avalanche conditions on specific terrain features where human-triggered avalanches are “possible.”
  • 1 тАФ Low: Generally safe avalanche conditions where slides are “unlikely.”

A timeline of avalanche events this season

Dec. 31:┬аA 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:┬аAvalanche 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:┬аTwo 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:┬аNolet dies of his injuries in hospital.

Jan. 21:┬аTwo 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:┬аHeli-skiers and their guide are caught in an avalanche near Revelstoke, B.C. The two guests, brothers and American businessmen Jon and Tim Kinsley,┬аare dug out of the snow unresponsive and are both declared dead in hospital. The guide is taken to hospital in stable condition.

Jan. 23:┬аA 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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