Avalanche Forecast
Issued: Mar 20th, 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
Moderate
Avalanche Summary
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.
On Saturday, numerous loose wet to size 1.5 were observed in steep, rocky solar terrain. Several natural storm slab avalanches were observed up to size 2.5, likely triggered by the sun or cornice failure. A few skier triggered, size 1, avalanches were reported. These avalanches released on a weak layer of surface hoar underneath the storm snow.
Snowpack Summary
Storm snow has settled with warm temperatures. A melt freeze crust or moist snow exists on the surface at low elevations and on sun affected slopes.
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
Monday Night
Partly cloudy. Light southwest winds at ridgetop. Treeline temperature low 0°C. Freezing levels 1500 m.
Tuesday
Mainly cloudy with isolated flurries, trace accumulation. Light southwest winds at ridgetop. Treeline temperature -1°C. Freezing levels 1200 m.
Wednesday
Mix of sun and cloud. Moderate southwest winds at ridgetop. Treeline temperature -2°C. Freezing levels 1000 m.
Thursday
Mainly sunny. Strong southwest winds at ridgetop. Treeline temperature -1°C. Freezing levels 1200 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
Storm snow has been redistributed by easterly winds into deep deposits in lees. A buried layer of surface hoar is increasing the reactivity and propagation of wind slabs.
Aspects: North, South, South West, West, 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 21st, 2023 4:00PM
