by Timothy Schafer Local Journalism Initiative Reporter on Thursday Jan 26 2023
There are deep layers of concern and uncertainty over deep layers of weak snow buried in the West Kootenay backcountry alpine regions that could create large avalanches.
Although there have been no avalanches reported in the West Kootenay region for the last two days, dangerous conditions still exist in the backcountry, according to Avalanche Canada (AC).
Persistent slabs — which are particularly difficult to forecast — permeate the alpine and treeline regions of the backcountry, said AC avalanche forecaster Ross Goddard in his report on Wednesday.
“With the rise in temperatures expect to see signs of instability like pinwheeling and tree bombs,” he said. “This could create smaller accumulated loading on the surface and trigger weak layers buried further down creating large avalanches.”
He strongly recommended making low-consequence choices of terrain that would not expose backcountry users to the consequences, if people chose to travel in avalanche terrain.
“Although persistent and deep persistent avalanches have been on the decline, warming that is expected to arrive on Thursday brings real concern for the potential for natural as well as human triggering of weak layers buried deeper in the snowpack,” Goddard explained in his report.
Avalanches have already claimed five lives in B.C. in 2023, said Bowinn Ma, minister of Emergency Management and Climate Readiness, in a statement released Wednesday.
“This year’s snowpack is being compared to 2003, which was one of the worst years for avalanche fatalities,” said Ma.
Avalanche Canada expects these conditions to last the remainder of the winter season in some areas.
Avalanche activity in the region has been sparse, with most activity (on Sunday) consisting of mainly of small (size 1 or less) dry loose releases from steeper terrain with skier traffic and ski cutting.
“For our neighbours to the north, several wind slab and persistent slab avalanches were reported that ranged in size from one to two,” said Goddard.
New snow — up to 20 centimetres — has buried a new weak layer.
The new snow consists of faceted snow, surface hoar (three to 10 millimetres) and a crust.
“The surface hoar is found in sheltered areas up to 2,200 metres and the crust is present on steep solar aspects,” Goddard said in his report. “Variable winds at high elevations have pushed this new snow around, creating wind slabs on a variety of aspects.”
A freezing rain or rime crust buried on Jan. 18 now sits about 15 to 30 cm deep, with other layers — crusts, facets and surface hoar — found in the upper snowpack between 30 to 50 cm down.
“They have yet to produce avalanche activity but they are something to keep an eye on,” Goddard said.
The principal concern right now in the West Kootenay backcountry is a surface hoar layer that developed in early January — down roughly 50-70 cm — along with a melt-freeze crust from late December (70-90 cm deep).
“These layers are responsible for our persistent slab problem,” said Goddard. “Our deep persistent slab problem stems from a weak layer created in mid-November and it is now buried 100 to 190 cm deep. These layers are a major concern and can produce large or even very large avalanches with human or machine triggers.”
Source: RGoddard, Avalanche Canada
Weather you go
Cloudy with possible late day sun, up to nine centimetres of accumulation focused mostly in the western area of the region; winds west at 15 kilometres per hour, gusting to 45 km/h.
Treeline temperatures will get to above zero degrees Celsius due to a temperature inversion, with freezing levels up to 700 metres.
A mix of sun and cloud, up to seven cm. accumulation in some parts of the region ending in the morning; winds northwest at 25 km/h.
Treeline temperatures around -5 C.
A mix of sun and cloud, up to four cm. accumulation; winds northeast 15 to 30 km/h.
Treeline temperatures at -17 C.
• More details can be found in the Mountain Weather Forecast.
Source: Avalanche Canada
Backcountry users should always check the avalanche forecast at: https://www.avalanche.ca/en/map
If you go
• Avoid steep, shallow and rocky terrain features. Everyone in a backcountry party needs the essential gear, such as a transceiver, shovel and probe, and the training to use them.
• Adopt a cautious mindset when in avalanche terrain.
• Be diligent about terrain choices. Sticking to slope angles of less than 30 degrees when in clearings, open trees and alpine terrain can help minimize risk.
• Follow disciplined group decision-making, ensuring that each group member is engaged in terrain selection.
• Minimize exposure to overhead hazards, given that these avalanches can be remotely triggered and travel far in runout zones.
• Travel one at a time when exposed to avalanche terrain and regroup in safe spots well away from overhead hazards.
• Avoid exposure to terrain traps, such as gullies, cliffs and trees, to reduce the risk of being caught in an avalanche.
• Practise patience, avoid complacency and accept that you may need to manage this risk for weeks or months to come.
Source: Avalanche Canada