Backcountry users were being advised to avoid steep, avalanche-prone terrain.
As of Wednesday, Jan 13, Avalanche Canada was forecasting a high risk of avalanche at and above the treeline in the North and South Columbia mountains.
The Revelstoke-based forecaster’s online report on mountain conditions stated snow and strong wind on Tuesday, Jan. 12, and into Wednesday morning would form fresh wind slabs, creating the risk of an avalanche. Wind slabs are formed out of drifted snow on the leeward side of steep slopes and can easily dislodge, creating an avalanche.
The high avalanche danger applied to alpine and treeline elevations, but below the treeline the avalanche danger remains considerable.
Along with the slabs created by the storm, Avalanche Canada’s forecast stated there were weak layers in the snowpack buried 50 to 80 centimetres, and 90 to 15 centimetres under the snow.
Avalanche forecaster Colin Garritty said with conditions as they are, backcountry users should be steering clear of avalanche terrain and sticking to forested and less steep slopes. He added that users should be aware of overhead hazards and the activities of others on the mountain.
Everyone in each group should carry safety essentials like shovels, probes and transceivers necessary for rescuing someone buried by an avalanche.
Garritty said human-triggered avalanches will remain likely in the coming days and conditions were such that they could be triggered naturally as well. Backcountry users should be on the lookout for signs of instability like cracking snow and small slides on low angle slopes.
Garritty said the snowfall accompanying Tuesday night’s storm took Avalanche Canada’s forecasters by surprise; while high winds were foreseen, heavy snowfall averaging 30 to 40 cm, but totalling 60 cm in some areas, was not.
Avalanche Canada had been receiving reports of avalanches in the area even before the storm on Jan. 12 and 13.
A group of backcountry skiers in an area called the gorge near the eastern end of Shuswap Lake reported setting off a “small but scary” avalanche as they were following a skin track on Jan. 12. The first avalanche was followed by a larger one, which ran downhill away from them for hundreds of metres through the trees. The report, sent to Avalanche Canada, also noted evidence of avalanches which came down before the group of four skiers arrived. The same group had skied the same slopes the day before and found conditions stable and good for skiing.