Avalanche Forecast
Issued: Mar 21st, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
lbaker,
Avalanche Canada
Hazard is improving as temperatures drop down to the valley bottom but be mindful that buried surface hoar continues to be reactive, especially in wind loaded features.
Summary
Confidence
Avalanche Summary
On Monday, a widespread natural loose wet avalanche cycle was observed, up to 2.5, below treeline. Numerous wet loose avalanches were observed size 1-1.5 on solar aspects at alpine and treeline. Three skier triggered, size 1, windslab avalanches were reported.
On Sunday, two, natural size 3 persistent slab avalanches were observed. Both these avalanches ran to valley bottom and are suspected to have released on a weak layer of surface hoar. Two, size 1.5 persistent slab avalanches were remotely triggered by a helicopter on the same layer.
Snowpack Summary
Storm snow has settled with warm temperatures. Below 1400 m moist snow or a refrozen melt freeze crust covers the surface. The crust extends up to 2000 m on solar aspects.
A weak layer of surface hoar is found 20-50 cm down in sheltered terrain. On solar aspects, this layer appears as a melt-freeze crust. This layer continues to be reactive to skier traffic.
A second weak layer of surface hoar and/or faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.
The remainder of the snowpack is consolidated and strong.
Weather Summary
Tuesday Night
Mainly cloudy with isolated flurries, trace accumulation. Light southwest winds at ridgetop. Treeline temperature -2°C. Freezing levels drop to 1000 m.
Wednesday
A mix of sun and cloud. Moderate southwest winds at ridgetop. Treeline temperature 0°C. Freezing levels 1100 m.
Thursday
Mainly cloudy with scattered flurries, 1-4 cm accumulation. Moderate southwest winds at ridgetop. Treeline temperature -1°C. Freezing levels 1000 m.
Friday
Partly cloudy with isolated flurries, trace accumulation. Light north winds at ridgetop. Treeline temperature -1°C. Freezing levels 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be carefull around freshly wind loaded features.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Problems
Wind Slabs
Southwest winds are redistributing available snow into fresh wind slabs in exposed lees at higher elevations. A buried layer of surface hoar is increasing the reactivity and propagation of wind slabs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of large surface hoar is found down 20-50 cm. This layer has been most active in the Shames region however with additional load we may see wider spread reactivity on this layer. Use caution on sheltered and shaded slopes where surface hoar is more likely to be preserved.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 22nd, 2023 4:00PM
