Avalanche Forecast
Issued: Feb 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Deep Persistent Slabs.
mbender,
Avalanche Canada
Continue choosing low consequence terrain. A complex, and generally weak snowpack is best managed by continuing to stick to lower angled terrain.
Summary
Confidence
Moderate
Avalanche Summary
On Monday there were a few loose dry avalanches size 1-1.5 reported in extreme terrain. On Sunday and several small (size 1-1.5) windslab avalanches were reported on various aspects in the alpine and at treeline. They were either triggered naturally, or by the weight of a rider on the slope.
Last Thursday, west of Invermere, a large (size 2.5), naturally triggered Deep Persistent Slab avalanche was reported. It was in the alpine, and it's suspected that it was triggered by a combination of windloading, and morning sun warming the slope.
The possibility remains of triggering facets near the base of the snowpack, particularly on shallow, rocky slopes.
Snowpack Summary
20-50 cm of snow since late January is settling, or has been redistributed by moderate southwest wind. This overlies another layer of windslab, or surface hoar sitting on facets or a thin sun crust.
50-70 cm below the surface, the mid-pack contains a layer buried in early to mid January that remains a concern. It mostly exists as surface hoar, but facets or a crust may also be present.
A layer from late November is found 75 to 150 cm deep and is part of a generally weak, faceted snowpack.
Snowpack depths range between 80 and 180 cm at treeline, with the shallowest depths found on the eastern edge of the region.
Weather Summary
Tuesday Night
Cloudy with flurries, accumulation 3-5cm. Moderate southwest ridgetop wind trending to strong at higher elevations. Treeline temperature around -4 °C.
Wednesday
Mix of sun and cloud. Moderate northwest ridgetop wind, possibly strong at high elevations. Treeline temperature around -6 °C.
Thursday
Mix of sun and cloud. Light to moderate southwest ridgetop wind. Treeline temperatures around -5 °C.
Friday
Cloudy with flurries. Moderate southwest ridgetop wind. Treeline temperature around -6°C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Approach lee and cross-loaded slopes with caution.
- Uncertainty is best managed through conservative terrain choices at this time.
- Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
Problems
Persistent Slabs
Several weak layers in the upper and middle portions of the snowpack are at prime depths for human triggering. Stay disciplined and choose low consequence lines. Use extra caution in steep, wind-sheltered terrain where buried surface hoar is most likely to be preserved. If triggered, persistent slabs could step down to deeper weak layers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
It remans possible that riders could trigger a weak layer of facets near the base of the snowpack. The most likely area to trigger it is in shallow areas with variable snow depths. Avoid thin and rocky start zones and select routes that avoid traveling through or under large avalanche paths.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 8th, 2023 4:00PM
