Avalanche Forecast
Issued: Feb 10th, 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.
cgarritty,
Avalanche Canada
Flurries and heightened winds will be forming new wind slabs on an ongoing basis through Saturday. Expect the size and reactivity of slabs to increase over the day and seek out sheltered terrain options away from overhead hazard to manage the situation. The chance for surface slabs to step down to a deep weak layer can't be ruled out.
Summary
Confidence
Avalanche Summary
Reports from Thursday included one size 1 (small) skier triggered wind slab with a 25 cm crown in the central part of the region as well as an observation one additional size 2, 50 cm-deep storm slab from the recent natural cycle. More extensive observations of this cycle were again reported farther south in the more heavily trafficked Selkirks and Monashees.
On Wednesday, clearer weather allowed for observations at higher elevations. A widespread storm slab avalanche cycle from the previous 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.
Snowpack Summary
Up to 20 cm of new snow is expected to accumulate over higher terrain in the region by end of day Saturday under the influence of strong southwest winds. This will add to 60-100 cm of storm snow from the last week with similar elevated winds.
The recent 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 shaded 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
Friday night
Cloudy with continuing flurries bringing 5-10 cm of new snow. Moderate to strong southwest winds.
Saturday
Cloudy with flurries bringing 5-10 cm of new snow. Moderate southwest winds. Treeline high temperatures around -4.
Sunday
Cloudy with increasing snowfall bringing 5-10 cm of new snow, continuing overnight. Light rain below about 1400 metres Strong southwest winds. Treeline high temperatures around -1 with freezing levels rising to 1600 meters.
Monday
Cloudy with easing flurries bringing about 5 cm of new snow. Light west winds. Treeline high temperatures around -5.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- 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, continuous strong winds have been building 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: Alpine, Treeline.
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: All elevations.
Likelihood
Expected Size
Valid until: Feb 11th, 2023 4:00PM
