Avalanche Forecast
Issued: Apr 9th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Cornices and Loose Wet.
astclair,
Avalanche Canada
Continue to make conservative terrain choices while the storm snow settles and stabilizes, especially where it has been re-distributed by wind. Minimize exposure to cornices and steep slopes in direct sun.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
Friday night: Partly cloudy, isolated light flurries, moderate wind becoming west/northwest, treeline temperatures near -7 C, freezing level dropping to valley bottom overnight.Â
Saturday: Sunny with afternoon cloud, isolated light flurries, moderate west/northwest wind, treeline temperatures -6 C, freezing level rising to 700 m and dropping to valley bottom overnight.
Sunday: Mix of sun and cloud, moderate northwest wind, treeline temperatures near -1 C, freezing level rising to 900 m and dropping to valley bottom overnight.
Monday: Sunny with afternoon cloud, light south wind, treeline temperatures near 0 C, freezing level rising to 1500 m.
Avalanche Summary
On Friday, operators reported several small to large (size 1-2.5) natural and explosive-triggered storm slab avalanches breaking up to 50 cm deep.
Large natural and explosive triggered glide slab avalanche activity has been ongoing for the past few weeks. Glide cracks releasing as full depth glide slab avalanches are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.
Snowpack Summary
20-30 cm of recent snow in the past 48 hours has been accompanied by periods of strong southwest wind and has formed a widespread storm slab problem. Winds are forecast to shift to northwest by midday Saturday, which may build more reactive slabs in lee features.
Cornices are large, looming, and capable of triggering large avalanches when they fail. Previous weak layers are now deeply buried and have not resulted in any recent avalanches. At lower elevations, the new snow is falling on a melt-freeze crust.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Avoid exposure to slopes that have cornices overhead.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Storm Slabs
20-30 of new snow has formed widespread storm slabs that may be possible to trigger. This problem will be more pronounced in wind-drifted areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines and have likely grown with the recent snow and wind.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
The potential for strong sun and rising temperatures midday may produce wet loose avalanches in the recent snow.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 10th, 2021 4:00PM
