Avalanche Forecast
Issued: Feb 9th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Persistent Slabs.
lbaker,
Avalanche Canada
Continue to choose conservative terrain and watch for signs of instability as strong winds continue to promote slab development in lees throughout the day.
Avoid shallow, rocky snowpack areas where triggering the deep persistent weak layer is still possible.
Summary
Confidence
Moderate
Avalanche Summary
On Wednesday, clearer weather allowed for observations at higher elevations. A widespread storm slab avalanche cycle from the past 24 to 48 hours was observed with avalanches from size 1.5 to 3. Most notable was a size 3 persistent slab avalanche that initiated on a steep north slope at 2000 m. The slab was 100-130 cm deep.
On Tuesday, a size one skier accidental avalanche was reported on a northwest feature below treeline.
On Sunday and Monday, several small natural wind slab avalanches were observed, up to size 1.5, at treeline on steep east-facing slopes.
Snowpack Summary
60-100 cm of storm snow from the last week continues to be redistributed by southwest winds. Storm snow sits above a plethora of old snow surfaces including previously wind-affected snow at upper elevations, a sun crust on steep solar aspects, faceted snow, and surface hoar crystals in wind-sheltered terrain.
In the upper meter of the snowpack sits two layers of surface hoar crystals and/or a melt-freeze crust. The surface hoar is most likely found around treeline and lower alpine elevations. The melt-freeze crust is found up to 1800 m on all aspects and into the alpine on sun-exposed slopes.
Large and weak facets from November are near the base of the snowpack and continue to produce very large avalanches in the region.
Weather Summary
Thursday Night
Cloudy with isolated flurries, 2-5 cm accumulation. Ridge wind from the southwest 40-60 km/h in the evening. Alpine temperatures rise to -3 C. Freezing level rises to 1200 meters.
Friday
Cloudy with sunny periods isolated flurries, 2-5 cm accumulation. Moderate southwest ridge wind switch to 20 km/h westerley winds mid-day. Alpine temperatures rise to -2 C. Freezing level rises to 1000 meters.
Saturday
Mix of sun and cloud with isolated flurries, 2-5 cm accumulation. West ridge wind 20 km/h gusting 40 km/h. Alpine temperatures rise to -3 C. Freezing level rises to 800 meters.
Sunday
Cloudy with scattered flurries, 5-10 cm accumulation. Ridge wind southwest 40-50 km/h. Alpine temperatures rise to -2 C. Freezing level rises to 1500 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
- Be especially cautious as you transition into wind affected terrain.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Make observations and asses conditions continually as you travel through the terrain, strong overnight winds have built fresh wind slabs on lee slopes. Slabs will likely be the deepest and most reactive on north and east aspects at treeline and above.
Keep in mind that wind slabs have the potential to step down to deeper weak layers, resulting in large and consequential avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure. See more on the potential of triggering deeper weak layers in our latest Forecasters' Blog.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Two surface hoar layers found in the upper 100 cm of the snowpack have been reactive in scattered areas around the region. Be especially cautious around steep openings within and near treeline elevations, especially where the recent storm snow has been wind affected.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 10th, 2023 4:00PM
