Avalanche Forecast
Issued: Apr 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
isnowsell,
Avalanche Canada
Riders must manage various avalanche concerns that vary by elevation and aspect. Observe your local conditions and let that inform your terrain choices.
Summary
Confidence
Moderate
Avalanche Summary
Avalanche activity appears to be slowing. However, many natural and human-triggered avalanches have been reported over the last week. Many of these are sliding on recently buried melt-freeze crusts, including a fatal avalanche in the western Purcells and a close call near Revelstoke.
Snowpack Summary
Dry, powder snow remains at higher elevations on north-facing terrain. While melt-freeze crusts or moist snow are likely to be found on steep solar slopes and at lower elevations.
A layer of surface hoar persists down roughly 50 to 100 cm from the surface. In all but true north-facing slopes the surface hoar likely sits on a melt-freeze crust and is responsible for numerous recent avalanches, some with surprisingly wide propagation.
The mid-snowpack is strong. However, the November depth hoar remains at the base of the snowpack and remains a concern in rocky, shallow, variable depth snowpack areas at treeline and above.
Weather Summary
Tuesday night
Mostly cloudy, with trace amounts of snow. Light west ridgetop winds. Treeline temperatures around -5 C. Freezing levels 500 m.
Wednesday
Cloudy with scattered flurries and a trace of snow. Light west ridgetop winds. Treeline temperatures around -5 C. Freezing level 1600 m.
Thursday
Cloudy with sunny periods in the afternoon. Light west ridgetop winds. Treeline temperatures 0 to -5 C. Freezing level 1900 m.
Friday
Mix of sun and cloud. Light ridgetop winds. Treeline temperatures 0 to -5 C. Freezing level 1900 m.
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.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
Problems
Storm Slabs
Scattered flurries continue to build storm slabs and may still need time to bond to underlying surfaces. Be especially cautious at higher elevations, near ridges and mountain tops were wind has likely increased slab depth and reactivity.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A layer buried on April 1, down roughly 50 to 100 cm from the surface, appears to be most reactive on solar tilted slopes where surface hoar may sit on a hard melt-freeze crust.
This layer is the culprit for the string of close calls over the last week and Saturdays fatal accident at Thunderwater Lake.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.
Suspect terrain includes steep, shallow, and rocky terrain where the snowpack varies between thin and thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 19th, 2023 4:00PM
