Avalanche Forecast
Issued: Feb 3rd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
Wind loading is expected on southerly slopes with a forecast change in wind direction, which is not the typical pattern for the region.
A persistent weak layer is now buried up to 100 cm. Avalanches on this layer will become harder to predict, so a conservative approach is key.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
WEDNESDAY NIGHT - Mainly cloudy with a few flurries / moderate to strong northwest wind / alpine low temperature near -10Â
THURSDAY - Mainly cloudy with a few flurries / moderate to strong northwest wind / alpine high temperature near -7
FRIDAY - Mainly cloudy / strong northwest wind, easing to moderate west wind / alpine high temperature near -5 / freezing level 1400 mÂ
SATURDAY - Mainly cloudy with scattered flurries / moderate to strong west wind / alpine high temperature near -7
Avalanche Summary
Human triggered avalanches are still expected to be easy to trigger in many areas.
There have been reports of numerous size 1-2 natural, human and explosives triggered avalanches every day since Saturday. Many of these avalanches have failed on the recently buried persistent weak layer.
Snowpack Summary
50-100 cm of recent fresh snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1900 m, and a sun crust on south-facing slopes. There could be more than 100 cm on this layer in wind loaded areas.
A crust from early December may be found around 200+ cm deep in the snowpack. In shallow rocky areas, it may still be possible to trigger this layer. In deeper snowpack areas, it appears to be unreactive.
Terrain and Travel
- Keep in mind that human triggering potential persists as natural avalanching tapers off.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Be aware of highly variable recent wind loading patterns.
Problems
Storm Slabs
Recent fresh snow combined with strong winds has formed reactive storm slabs in many areas, especially wind loaded terrain features. Be aware of the possibility for wind loading on southerly aspects with strong notherly winds in the forecast.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
50-100 cm of snow sits on a widespread weak layer that consists of facets, surface hoar, or a crust depending on location. Avalanches may propagate widely on this layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 4th, 2021 4:00PM
