A buried ice crust is raising alarm bells for those who patrol B.C.’s backcountry.
“We are concerned,” said Ilya Storm, a public avalanche forecaster with the B.C. Avalanche Centre in Revelstoke.
The crust was formed during the Pineapple Express weather system, which much of B.C. saw in early December. It dropped rain on the top of most mountains, which then froze to form a hard surface.
The snow that fell on top of that ice crust turned to the consistency of coarse salt — like little ball bearings — which have little cohesiveness, making whatever snow fell since unstable and ready to roll.
“This year the layer condition is a little harder to predict and a little less forgiving so we are really asking people to stay disciplined and to make better choices than the steepest, largest slope out there,” said Storm.
“These are the days to enjoy the powder on gentle terrain, smaller terrain features.”
It’s likely the ice crust played a role in the 100 Mile House avalanche last week, which claimed the lives of two snowmobilers.
Four people died in avalanches in Canada in December. In an average year there is only one death.
The areas of greatest concern are where the ice crust is about one metre below the surface of the snow. At risk areas include the south Rockies, Crowsnest, Fernie, the Kootenay Boundary area and the Purcell Mountains west of Invermere and Golden.
In the Coast Mountains conditions are slightly different. According to Whistler-Blackcomb’s Jan. 2 Avalanche Advisory, the Dec. 4 raincrust is getting buried, but can still be found on the surface at ridgelines and some windward slopes. These layers “may be a persistent weakness in some areas well into the season.” The advisory also says the forecast is for heavy snowfall and warming temperatures this week “will be the first real test of these weaknesses, and you can expect to see some significant natural avalanching to occur.”
The Whistler-Blackcomb Avalanche Advisory is updated daily at www.whistlerbalckcomb.com/weather/advisory
There are now daily updates to the B.C. Avalanche Centre’s web pages and in the New Year further changes will be made to the site to offer even more specific information by region.
“People should check for the most recent update on conditions at www.avalanche.ca ,” said Storm.
“People’s perceptions of the conditions and the risks are not the same as the actual conditions.
“Everyone wants to come home safe and so we are trying to get the message out that it is tricky right now. This year is a little bit different than last year.”
Storm suggests that mountain users take to the slopes one at a time, and every time a person heads downhill they should already have an escape plan in mind should they trigger an avalanche. They should also carry avalanche gear and know how to use it.
And if backcountry enthusiasts aren’t sure about safety they should dig down until they find the ice crust so they know the potential for how much snow could release.
“This crust is going to be with us for the next several weeks so although many things about the upper snow crust surface and the conditions will evolve this crust is not going to go away any time soon,” said Storm.