Avalanche Forecast
Issued: Mar 14th, 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 at higher elevations.
Summary
Confidence
Avalanche Summary
We received a report of a small (size 1) wind slab avalanche on north facing, steep terrain from Tuesday.
Looking forward, progressive snowfall with southerly wind could continue to form wind slabs that could become touchy to riders.
Snowpack Summary
Around 10 to 20 cm of snow overlies large (10 mm) surface hoar crystals in terrain sheltered from the wind, wind-affected snow in wind exposed terrain, and a hard melt-freeze crust on sun-exposed slopes. Wind has shifted from the north to the south meaning that wind slabs may be found on all aspects.
The middle of the snowpack is strong and contains numerous hard crusts.
The lower snowpack is composed of weak basal facets. The layer is currently dormant but it may become active with any rapid change to the snowpack, such as rapid loading (e.g., heavy snowfall or rain) or prolonged and extensive warming. Avoiding thin and rocky slopes is still recommended. Cornices are also very large and a cornice failure could trigger this basal layer.
Weather Summary
Tuesday Night
Cloudy with snowfall, accumulation 5 cm, 20 to 30 km/h south wind, treeline temperature -10 °C.
Wednesday
Cloudy with snowfall and periods of clearing, accumulation 5 cm, 30 km/h southwest wind, treeline temperature -9 °C.
ThursdayCloudy with snowfall, accumulation 5 to 10 cm, 30 km/h south wind, treeline temperature -6 °C, freezing level rising to 1000 m.
FridayPartly cloudy with no precipitation, 30 to 40 km/h southeast wind, treeline temperature -4 °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, or extensive warming. Cornices are also very large at this time of year and a cornice failure could trigger this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 15th, 2023 4:00PM
