Avalanche Forecast
Issued: Mar 13th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
mconlan,
Avalanche Canada
Continue to assess for wind slabs in steep terrain.
Summary
Confidence
Moderate
Avalanche Summary
Riders observed evidence of naturally triggered wind slab avalanches from the past few days, mostly occurring on north aspects in the alpine.
Snowpack Summary
Around 10 cm of snow overlies large (10 mm) surface hoar crystals in terrain sheltered from the wind. Wind affected snow is predominant on all aspects in wind-exposed terrain due to variable wind directions. A hard melt-freeze crust is likely found on sun-exposed slopes.
Several hard crusts with associated weak facets and/or weak layers of surface hoar can be found in the top 150 cm of the snowpack. These layers haven't produced recent avalanche activity or alarming snowpack test results but they remain on our radar.
The lower snowpack consists of weak basal facets, which may become active with any rapid change to the snowpack, such as rapid loading (e.g., heavy snowfall, cornice fall) or prolonged and extensive warming. Avoiding thin and rocky slopes is still recommended.
Weather Summary
Monday Night
Cloudy with snowfall, accumulation 2 to 5 cm, 20 km/h southwest wind, treeline temperature -12 °C.
Tuesday
Mix of sun and cloud with isolated flurries, accumulation 1 to 3 cm, 20 to 30 km/h south wind, treeline temperature -11 °C.
WednesdayCloudy with snowfall then clearing, accumulation 2 to 5 cm, 40 to 50 km/h southwest wind, treeline temperature -10 °C.
ThursdayCloudy with snowfall, accumulation 2 to 5 cm, 30 to 40 km/h south wind, treeline temperature -5 °C, freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully evaluate steep lines for wind slabs.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Conditions may have improved, but be mindful that deep instabilities are still present.
Problems
Wind Slabs
Wind slabs may be found at higher elevations, particularly in steep terrain adjacent to ridgelines. The wind has shifted directions, meaning slabs may be found on all aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak, sugary faceted grains exist near the base of the snowpack. Riders are most likely to trigger this layer in steep, rocky slopes where the snowpack is inherently thin. The likelihood of avalanche activity on this layer will increase during periods of rapid change to the snowpack, such as heavy snowfall, rain, extensive warming, or large loads like a cornice fall.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 14th, 2023 4:00PM
