Avalanche Forecast
Issued: Mar 6th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Storm Slabs.
mconlan,
Avalanche Canada
Storm slabs may build over the day, with the most snow expected in the east of the region. This snow will continue to load a buried weak layer. Don't be complacent, as this layer continues to surprise people.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 cm, light southwest wind, alpine temperature -4 C, freezing level 1400 m.
SATURDAY: Cloudy with snowfall, accumulation 10 to 15 cm in the east of the region, 5 cm in the west of the region, light to moderate southwest wind, alpine temperature -5 C, freezing level 1200 m.
SUNDAY: Mix of sun and cloud with isolated flurries, light southwest wind, alpine temperature -8 C, freezing level 1100 m.
MONDAY: Clear skies, light southwest wind, alpine temperature -7 C, freezing level 1200 m.
Avalanche Summary
On Thursday, a large wind slab avalanche was observed in the west of the region. It released naturally on a northwest aspect in the alpine and the slab was about 20 cm deep. Otherwise, some cracking was observed in wind-affected snow.
Over the past week, small to large (size 1 to 2) avalanches have released on the surface hoar layer described in the Snowpack Summary. They have most often released between 1800 and 2300 m on northwest to east aspects. This trend is suspected to continue as this layer slowly gains strength.
Snowpack Summary
The region is expected to see 10 to 20 cm of snow by Saturday afternoon, with the most in the east of the region. Storm slabs will develop over the day. The wind is expected to stay light to moderate from the southwest, so wind slab formation may be limited to immediate lee features.Â
The snowfall will load a touchy layer of feathery surface hoar crystals that is found 30 to 50 cm deep. The layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around upper below treeline, treeline, and lower alpine elevations. Check out the latest forecaster blog that offers a deeper dive into these conditions.
The remainder of the snowpack is strong and well-settled.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Watch for fresh storm slabs building throughout the day.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Carefully evaluate steep lines for wind slabs.
Problems
Persistent Slabs
Around 30 to 50 cm of snow overlies a weak layer of surface hoar. The layer has been most problematic on northwest to northeast aspects between 1600 m and 2300 m, but the layer may exist on all aspects and at all elevations. Riders will be capable of triggering this layer for some time until there is a substantial change in the snowpack. Assess the layer prior to committing to avalanche terrain or adopt a conservative mindset to avoid the problem.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Storm slabs may build over the day, as 10 to 20 cm of snow is forecast to Saturday afternoon. The snow may form slab properties quickly in lee terrain features, with light to moderate southwest wind forecast. If triggered, storm slabs could step down to the buried surface hoar layer, forming large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 7th, 2020 5:00PM
