Avalanche Forecast
Issued: Feb 5th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
trettie,
Avalanche Canada
Carefully assess snowpack conditions as you gain elevation. A tricky weak layer exists in the alpine and new wind slabs are likely to increase in size and reactivity.
Summary
Confidence
Moderate
Avalanche Summary
This MIN discusses new wind slab formation. We expect wind slabs to increase in size and reactivity.
A couple of large (size 2-3) persistent slab, human-triggered and natural avalanches were reported last week. These avalanches occurred near ridgetops in north-to-northeast alpine terrain. These avalanches have shown an impressive capability to propagate across large distances. Here is a link to the most recent human-triggered size 3 avalanche.
If you are out in the backcountry please consider filling out a Mountain Information Network report.
Snowpack Summary
New snow continues to accumulate with southwest winds forming wind slabs on north and east aspects. New snow is resting on a variety of wind-affected surfaces and crusts with small surface hoar in places in the alpine. Below roughly 1700 m a widespread 5-10cm melt-freeze crust is present at or near the surface.
A concerning persistent weak layer of surface hoar and/or facets is 50-80 cm deep and exists on north facing alpine features.
Check out this MIN from our field team to learn more.
Weather Summary
Sunday Night
Cloudy with up to 10cm of new snow possible. Moderate to strong southerly winds and a low of -5 at 1500m.
Monday
Increasing cloud throughout the day with up to 5cm of new snow expected. Light to moderate southwest winds and a high of -5 at 1500m.
Tuesday
A mix of sun and cloud with up to 5cm of new snow expected. Moderate south winds and a high of -5 at 1500m.
Wednesday
A mix of sun and cloud with flurries bringing a few centimeters of new snow. Light to moderate southwest winds and a high of -8 at 1500m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- In times of uncertainty conservative terrain choices are our best defense.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Persistent slabs have potential to pull back to lower angle terrain.
- Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
Problems
Persistent Slabs
Buried weak layers have recently produced large, surprising avalanches. The most recent avalanche activity has been observed on north to northeast alpine terrain on preserved surface hoar buried 50-80 cm. Keep in mind the potential for remotely triggered avalanches and how far these large avalanches can run into flatter terrain.
Stiff slabs can pull back into flatter terrain above them. These layers will be easier to trigger where the snowpack is thin.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
New snow and ongoing southwest winds will form wind slabs on north and east aspects. These new wind slabs likely won't bond well to the underlying surfaces.
Avoid steep rocky slopes near ridge crests where these slabs might be capable of stepping down to deeper layers.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 6th, 2023 4:00PM
