White minefield

Mountain passes ranging all the way from the B.C. coast to the Alberta border are on high alert against avalanches – but the real danger comes when the winter snowstorms end, a senior forecaster says.

The Sea-to-Sky, Kootenay Boundary, Purcells, South Columbia and Lizard Range regions are particularly at high risk, a bulletin issued by the Canadian Avalanche Centre stated. These areas were listed at a risk level of four on the North American five-point scale.

“The slopes are primed for a trigger,” said Ilya Storm, the centre’s senior avalanche forecaster. “It can just be a person who hits the wrong spot, a bit like a minefield.”

Below-average precipitation for December has caused the heightened risk of avalanches in these areas.

“In the interior, new snow is falling on a weak layer that was created in the middle of December’s drought,” Mr. Storm said. “So this is the first time the layer of surface hoar is being really overloaded with a new dump of snow which will likely result in a widespread avalanche cycle.”

A series of small storms has dropped 60 to 100 centimetres of snow on this weak base layer. The centre estimates upcoming storms could add up to another 50 centimetres on top of that.

A strong snow pack typically requires 20 centimetres of snow a day over a period of four to five nights – something that didn’t happen this month, Mr. Storm said.

“The longer the surface is exposed to the elements, the more difficult it is for new snow to bond to it,” Mr. Storm said. “So if you tell me that I’ve got a month between snowfalls, I’m going to tell you that in a month we’re going to have problems.”

The current avalanche cycle is being driven by new snow and wind in the southern half of the province. The centre reported a number of recent natural and human-triggered avalanches in the Sea-to-Sky regions, which includes the Whistler Blackcomb ski resort.

Anton Horvath, an avalanche forecaster at the resort, said there are still areas in the high alpine regions that staff were unable to clear due to 20 centimetres of snow Wednesday.

“A high danger rating is typical for us at this stage of the season,” Mr. Horvath said. “But this season we had an unusual early-season snow pack which caused a deep weakness.”

Backcountry skiing is becoming increasingly popular at the resort, he said. But despite posted advisories, he said more and more people are going without proper equipment or training.

Meanwhile, Eric Whittle, marketing director at the Kicking Horse Mountain resort near Golden, confirmed reports of an avalanche Wednesday. But he said it was deliberately triggered by the resort’s safety team as a precautionary measure in light of a recent warming trend.

The recent dump of snow also temporarily closed down numerous highways this week. Kootenay Pass on Highway 3 and Highway 23 from Revelstoke to Mica Dam were closed until mid-afternoon due to avalanche risk. Rogers Pass on the Trans-Canada Highway was closed but was due to be reopened later Wednesday.

But back on the slopes, Mr. Storm said as long as people educate themselves about the conditions, the risk is minimal. The true danger comes when the winter storms have abated.

“The real challenge will be when the skies clear, once the natural avalanche cycle ends, when there are all kinds of new powdered snow and people are going to be really tempted to go out,” he said.

More than 90 per cent of people who die in avalanches cause them themselves, Mr. Storm said.

There has only been one avalanche fatality so far this season.

According to the centre’s records, there were an average of 13 recreational avalanche fatalities a year between 1997 and 2007 across Canada – more than three-quarters of them in B.C.

More than 80 per cent of the fatal avalanche incidents happened when the regional avalanche danger rating was level three or higher, and signs of unstable snow were present prior to the accidents in a third of the cases.

But Mr. Storm said it would be wrong to label snowmobilers and skiers as “reckless.”

“The avalanche problem is a complicated one,” he said. “I really don’t believe that people go out to have fun in the mountains with the intention of not coming home.”