“You can’t read the Avalanche Conditions Report and make it apply to backcountry skiing,” Jennifer Magnuson warns me.

She’s the communication analyst for the Department of Highways and Public Works. She’s talking about the frequent reports they make on highway conditions, specifically avalanches in about four areas of highways known for frequent avalanches.

She’s seen people refer to their site when asking questions about the backcountry and, frankly, she’s nervous about that. “We can’t guarantee anything — but certainly our data only represents the highway corridor.”

Magnuson and I are flying in a helicopter to the top of a mountain near the B.C. border, along the highway corridor: “The data we collect for the highways can’t be applied to backcountry because we don’t collect information from more than one or two data points. It’s dangerous to assume one tells you about the other.”

She tells me about the drifts — about how wind is the biggest factor determining how and when avalanches occur. A day of wind can move the snow around, creating weighty drifts that suddenly trigger an avalanche and dump onto a highway.

We land the helicopter in a deep patch of snow. I duck my head until the blades stop spinning. Up here, the view is complete — a wide-angle lens of the whole valley — and it probably looks to a skier as if every hill and mountain around is a mogul to be skied around and jumped off.

Already, we’ve seen ski tracks up the hills on our way here, so we know there’s been good use on all the snow we’ve gotten this year.

People do read the Department of Highways and Public Works site to see if they can travel to these remote areas for skiing — and this is good, but, “we just don’t want people to get a false sense of security. They say, ‘Oh, looks like there’s a low risk of avalanche’… but even the mountain behind the corridor can have radically different conditions.”

She suggests being aware of where the risks are if you go backcountry. “And always wear an avalanche beacon.”

I’m wearing mine, even before I get to a mountain. It fits into a pocket and rescue teams can find you if you get buried under snow.

“A snow probe is something you can carry in your car, too,” Magnuson adds.

Because avalanches on the highway can come fast and a snow probe is another way for crews to find you and your car.

Shovel, flashlight, flares, warm blankets, winter gear, extra food and water — all of these, Magnuson reiterates to me, are important for everyone to have in their car.

“Road conditions can change rapidly. We want to make the public as safe as possible out there.”

And up here on the mountain, Hector MacKenzie and his son, Colin, are doing just that.

The MacKenzies have dug a hole in the snow, down to the bottom, to look at the individual layers. They are like archaeologists on a dig, going back in time, to the first snow of the season.

“Or like geologists,” I say to them.

“Well it is a lot like geology because a lot of geology is about sheer stresses and exposure and lifts and drops. I had a nephew, who’s a geophysicist, come out with me and he made the same analogy. It’s just that here it can happen like that,” and he snaps his fingers, “whereas in geology it can take eons.”

Colin is in the hole, measuring, taking out different tools to talk about the different kinds of snow he’s seeing. Hector is recording the data, training Colin.

They check the temperatures of several layers of snow. Hector checks foot penetration, and he has his whole body memorized in sections of centimetres to find out how far he goes down with a heavy step. “Seventy five,” he says, after sinking into the snow. “My hip is 100cm, my kneecap 50cm, so mid-thigh is 75.”

He tells me why we’re checking these spots — because they are representative of the kind of snow this area has received.

“We’re going to check these two spots. Partly because there are only two convenient spots to check, but also because the most active avalanche zone is just north of the border and south of the border. Then we’ll go up about 10 kilometres down to the south end of Tutshi where it’s not nearly as active as this area.”

Some of the snow is crystal-like. “Looks like diamonds, doesn’t it?” Hector says to me.

“That’s a very dangerous snow … when it gets pretty like that. Not at first, but wait til it gets buried under another dumping of snow.” The snow has crystallized, he tells me, and it’s lost a lot of water-vapour, and condenses and it doesn’t bond with the snow below, an any new snow that might come along.

He tries to show me with his hands and explain how sometimes new snow, when it falls, doesn’t grab hold of the snow below. He shows me how if the snow doesn’t have the kinds of edges that will connect to the snow before, then it creates a dangerous layer that can sheer off with the right conditions.

Colin does a test involving a shovel flat on the surface of the snow, hitting it, as it goes into the snow and looking for how far down the snow reacts, where it suddenly creases. Then he cuts a square of it up top and pulls the square slowly toward him to see where it’s going to break. And when it breaks it breaks in a sheer flat surface a cement layer would love.

Skiers, however, wouldn’t.

Avalanches aren’t only caused by these layers that haven’t connected. There are a lot of factors that can break up those layers of snow. Rain, rising temperatures, different kinds of snow.

“But not sound,” they all tell me. “That’s a myth.” I’ve asked them if I yell too loudly if I would cause an avalanche. “Where did you get that? The Sound of Music?”

Julie Andrews never caused an avalanche as far as I know, but the movies portray avalanches as sound-driven — a clear myth.

When an avalanche does occur, the crews of the Department of Highways and Public Works (HPW) will work hard to clear a road that’s been suddenly overwhelmed by an avalanche — all day — but not at night.

At night, there’s too much danger of not seeing another avalanche coming.

There are many slides between KM 81.4 and 84 that could trap anyone travelling in the area. HPW will determine how to keep the public safe, how and when to close roads, when to post safety alerts. They do everything they can to keep the public safe on the highways.

“But we need people to take their own precautions, too, whenever they go skiing or sledding.” The reports only warn of possibilities, says Magnuson.

The rest is on us.