Avalanche Forecast
Issued: Mar 13th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices, Persistent Slabs and Loose Wet.
JSmith,
Avalanche Canada
Overhead hazards such as cornice failures or small wet loose avalanches triggering large persistent slab avalanches will be the primary concern on Sunday. Pay attention to what's above your head and back off of slopes if the snow surface becomes moist.
Summary
Confidence
Moderate - Uncertainty is due to whether buried persistent weak layers become active, triggering avalanches, with the arrival of the forecast weather.
Weather Forecast
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SATURDAY NIGHT: Clear / Moderate, southwest ridgetop wind / alpine low temperature 0 / Above freezing layer of air 1000-2000m.
SUNDAY: Sunny / Moderate, southwest ridgetop wind / alpine high temperature 4 / Freezing level 2300 m.
MONDAY: Mix of sun and cloud / Light, west ridgetop wind / alpine high temperature 3 / Freezing level 2100 m.
TUESDAY: Sunny / Light, west ridgetop wind / alpine high temperature 2 / Freezing level 2100 m.
Avalanche Summary
Naturally triggered wet loose avalanches were reported up to size 1.5 on solar aspects at all elevations on Friday.Â
Rapidly rising freezing levels and sunny skies are expected to elevate the avalanche hazard through the weekend.
Snowpack Summary
Dry snow can be found on shaded aspects at upper elevations. On solar aspects and at lower elevations expect crusty snow in the morning and soft, moist snow in the afternoon. Lingering wind slabs and large cornices still pose a hazard close to alpine ridgelines.
A Persistent weak layer of facets 40-60 cm. deep that was buried in mid-February was reactive in the north of the region earlier this month but no avalanches have been reported on this layer since Mar. 3rd. There are several other weak layers deeper in the snowpack composed of old surface hoar, facets and/or crusts, all of which have been recently unreactive.
Big warm ups can awaken dormant weak layers resulting in large avalanches. Steep, rocky, convex terrain with a shallow or thin to thick snowpack are examples of places where triggering these layers are more likely.
Sunshine and warm temperatures often cause large cornice failures which are hazardous on their own and can also trigger large avalanches on deeper weak layers that the weight of a single rider would not trigger.
Terrain and Travel
- Avoid exposure to slopes that have cornices overhead.
- Cornice failure may trigger large avalanches.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Problems
Cornices
Rapidly rising freezing levels and sunny skies significantly increase the likelihood of cornice failures which are hazardous on their own and can also trigger large avalanches on deeper weak layers that the weight of a single rider would not trigger. Avoid exposure to slopes that have cornices overhead.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
Big warm ups can awaken dormant weak layers resulting in large avalanches. Steep, rocky, convex terrain with a shallow or thin to thick snowpack are examples of places where triggering these layers are more likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Naturally triggered wet loose avalanches are possible; especially on steep solar aspects in the alpine.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 14th, 2021 4:00PM
