Avalanche Forecast
Issued: Jan 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
ahanna,
Avalanche Canada
Keep buried weak layers and potential for persistent slab avalanches in your mind. The likelihood of triggering them may be diminishing but if you're unlucky enough to do so, consequences are high. A complex snowpack like this is best managed with conservative terrain choices.
Summary
Confidence
Weather Forecast
Friday night: Clear, calm to light west wind, freezing level valley bottom.
Saturday: Mainly sunny, light southwest wind, alpine high -7, freezing level valley bottom.
Sunday: Mix of sun and cloud, light west wind, alpine high temperature near -7, freezing level valley bottom.
Monday: Mix of sun and cloud, moderate southwest wind, alpine high -7, freezing level 900 m.
Avalanche Summary
A few natural, human and explosive triggered wind slabs size 1-2 were reported across the region in the latter part of the week.
Two human triggered avalanche incidents occurred on Tuesday; a size 1.5 on surface hoar in a northeast facing burn near Glacier National Park (view MIN report here), and a size 2.5 avalanche on an east aspect at treeline in the Lower Holt area, near Golden (view report here). Thankfully there were no injuries.
A notable avalanche from the natural storm cycle that occurred last weekend include a natural size 2.5 deep persistent slab avalanche reported on a north aspect at 2500 m near Invermere.
Snowpack Summary
Recent snow with strong southerly wind has formed wind slabs in leeward terrain features at upper elevations.
There are currently several layers of concern in the regional snowpack. 40-60 cm of snow sits on a weak layer of surface hoar that was reported in the Golden area.
The mid-December crust and/or surface hoar is now down 90-140 cm. Although there have been no new reports of avalanches on this layer in the last few days, it remains possible to trigger where it is well preserved.
The lower snowpack is characterized by more crusts, the most notable is a rain crust from early November that is near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers in steep, shallow, rocky areas with a thin to thick snowpack.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Wind Slabs
Recent new snow and strong southwest winds have formed wind slabs in lee terrain.
Aspects: North, North East, East, South East, North West.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar is down 50-100 cm, and may still triggerable by humans in areas where it exists.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A crust buried near the bottom of the snowpack has been responsible for at least one large avalanches in the past week.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 9th, 2021 4:00PM
