Avalanche Forecast
Issued: Apr 11th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Loose Dry.
zryan,
Avalanche Canada
Don't let good weather lure you into dangerous terrain.
Dry storm snow may be seeing its first test of strong sun, and avalanche danger could increase rapidly.
Summary
Confidence
Moderate
Avalanche Summary
On Saturday, a large (size 2-3) skier-triggered wind slab occurred on a northwest aspect in the alpine in the Duffey on Blowdown Peak. Details can be seen in this MIN report.
Large wind slabs were easily triggered by skiers on Monday. A size 2.5 skier-triggered wind slab was reported in the Duffey. This avalanche occurred on a northeast aspect in the alpine in steep, rocky, wind-affected terrain. A second size 2 skier-triggered wind slab was reported in the South Chilcotins. This avalanche was triggered remotely from an adjacent slope in south-facing alpine terrain. Two large (size 2-3) natural wind slabs were observed from east-facing alpine and treeline terrain.
Looking forward to Wednesday, we suspect that rider triggerable wind slabs may still be found at treeline and above. Strong solar input has the potential to rapidly destabilize the dry surface snow. Back off steep sun-exposed slopes and avoid overhead exposure during periods of strong sun.
Snowpack Summary
Up to 60 cm of recent storm snow and strong southerly winds have formed wind slabs on west through east aspects at upper elevations. These winds have also formed large cornices. A crust exists on or near the surface on all aspects at treeline and below.
A crust from early April can be found down 30 to 60 cm on all solar aspects and at treeline and below on north-facing terrain. Below this crust, the mid-pack is generally well settled.
The base of the snowpack remains faceted and weak. Avalanche activity has not been observed on this layer recently but concern remains for shallow rocky snowpack areas.
Weather Summary
Tuesday night
Clear periods with isolated flurries. Alpine temperatures drop to a low of -11 °C. Ridge wind light from the north. Freezing level at valley bottom.
Wednesday
A mix of sun and cloud. Alpine temperatures reach a high of -3 °C. Ridge wind light from the north. Freezing level rises to 1600 metres.
Thursday
Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -4 °C. Ridge wind light from the southwest. Freezing level rises to 1500 metres.
Friday
Sunny with cloudy periods. Alpine temperatures reach a high of -2 °C. Ridge wind light from the southwest. Freezing level rises to 1700 metres.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be alert to conditions that change with elevation and sun exposure.
- Be especially cautious as you transition into wind affected terrain.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Wind Slabs
20-60 cm of storm snow and southerly winds have formed wind slabs in lee and cross-loaded terrain at treeline and above.
Aspects: North, North East, East, South East, South, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Recent storms have formed large and fragile cornices. Be especially cautious during periods of strong sun, natural cornice failures have the potential to initiate large slab avalanches on the slopes below.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Dry
Strong solar input may rapidly impact the surface snow, initiating dry loose avalanches from steep terrain.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 12th, 2023 4:00PM
