The avalanche threat is easing throughout British Columbia, but any slide that does happen could be a big one, the Canadian Avalanche Centre says.
"We are moving into a situation of low probability but high consequence," said Karl Klassen, manager of the CAC's Public Avalanche Warning Services. "It is difficult for the CAC to issue further warnings because of the low probability, but this doesn't mean the backcountry is safe."
Jan Tindale, Whistler-Blackcomb avalanche forecaster, agrees with that assessment and adds that users of the backcountry must remain vigilant. She said that although high and extreme danger warnings typically keep people off mountains, they return when danger levels are low, mistakenly believing they are safe. "Often the most danger is when there is a moderate rating."
The CAC issued a special public avalanche warning for the mountains of the B.C. Interior last Thursday, pointing to two metres of fresh snow falling on top of a weak, unstable snow base above the tree line. Mr. Klassen said that the risk will likely decrease in coming days; the CAC let the special warning expire on Monday afternoon, but maintained a high-risk rating for some Interior mountains. "This situation is common this time of year and we expect to move back into a pattern of weather dictating risk," Mr. Klassen said.
Although conditions have improved, the CAC continues to advise all recreational backcountry users to make "consistently cautious" decisions, and to avoid avalanche-prone terrain.
Mr. Klassen outlined three recommendations for people heading into the backcountry. First, local knowledge is key, so people need to know where previous avalanches have occurred. People need to be aware of weather changes. Second, extreme conditions are the most obvious cause of avalanches, but even the sun coming out can trigger a slide. And finally, he pointed to terrain choice as a key to staying safe. "Shallow snow is bad; if you are heading up the mountain, you better understand what is under your feet and what risks it poses," he said.
The CAC recommends that all members of a backcountry party be equipped with a shovel, probe and transceiver, and strongly encourages all backcountry users take an avalanche safety training course. "There is no such thing as zero risk in the mountains," Mr. Klassen said. "Preparation is the most important thing people can do to stay safe."